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A number of epidemiological studies have reported that chronic exposure to high concentrations of fluoride not only causes dental and skeletal fluorosis but additionally affects serum levels of reproductive hormones. However, possible interaction between fluoride exposure and estrogen receptor alpha (ESRα) gene polymorphisms on sex hormone-binding globulin (SHBG) and androgen binding protein (ABP) of male farmers has not been detailed. Here, we conducted a cross-sectional study including 348 male farmers with different fluoride exposure levels from drinking water in Henan province of China to explore effects of fluoride exposure and ESRα genetic variation on serum SHBG and ABP levels. We found serum SHBG levels in male farmers from the high exposure group to be lower than those of the low exposure group. We also found that concentrations of SHBG affected ABP levels. Furthermore, fluoride exposure and single nucleotide polymorphisms at the XbaI and rs3798577 loci of the ESRα gene affected serum ABP levels. Our findings suggest that chronic fluoride exposure from drinking water is associated with alterations of serum SHBG and ABP concentrations in local male farmers and that the effect of fluoride exposure on ABP levels vary depending on ESRα gene polymorphisms., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Many studies have demonstrated that exposure to excess fluoride was associated with a variety of diseases. Little is known about the variation of testosterone (T) levels caused by fluoride exposure. The aim of this study is to explore the association of fluoride exposure and age with serum T and androgen-binding protein (ABP) levels in male farmers. A cross-sectional study was conducted in a county of Henan Province, China, including high fluoride exposure from drinking water villages and control villages. Male farmers aged 18-55 years old who lived in these villages were recruited by cluster sampling and divided into a higher fluoride exposure group (HFG) and a lower fluoride exposure group (LFG) according to the level of urinary fluoride. Levels of T and ABP in serum were measured using chemiluminescence immunoassay (CLIA) and enzyme-linked immunosorbent assay (ELISA) respectively. Markedly lower T levels were observed in male farmers from the HFG than in those from the LFG (t = 2.496, P < 0.05). Furthermore, younger farmers, 18-29 and 30-39 years old, may be the most likely to have lower T levels when exposed to fluoride (P < 0.05). No significant differences were observed in serum ABP levels in all male farmers between the two groups with different fluoride exposure. These results supported that excess fluoride exposure decreased serum T levels of male farmers with age-specificity.

Objective: To explore the influence of water fluoride exposure on sex hormone binding globulin (SHBG) and testosterone in adult male., Methods: Cross-sectional study was conducted in three villages of Tongxu county including high fluoride group (HFG), defluoridation project group (DFPG) and control group (CG) based on the fluoride concentration in drinking water. Adult male who were born and raised in the village and aged 18 - 50 years old were recruited using cluster sampling. Fasting blood and morning urine samples were collected. The fluoride levels in drinking water and urine were detected by fluoride-ion selective electrode method. Serum SHBG level was determined using enzyme-linked immunosorbent assay (ELISA). The chemical luminescence immune analysis method was used to detect serum testosterone content., Results: Serum SHBG level was 47.85 nmol/L in CG, 31.37 nmol/L in DFPG and 24.52 nmol/L in HFG respectively. There were significant difference among of three groups (P < 0.05). Serum testosterone level was 3.69 ng/ml in CG, 4.61 ng/ml in DFPG and 4.83 ng/ml in HFG respectively. Serum testosterone level in HFG was significantly higher than that in CG (P < 0.05). Serum SHBG level in HFG has positive correlation with serum testosterone (r = 0.230, P = 0.049), which has not been observed in DFPG and CG., Conclusions: Long-time fluorine exposure may affect serum SHBG and testosterone level in adult male.

Introduction: The most widely used method for measuring free testosterone (FT) is by analog immunoassay (aFT); however, this assay has been criticized as unreliable based on laboratory studies in small groups of men. Calculated FT (cFT), derived from total testosterone (TT) and sex-hormone binding globulin (SHBG) values has been recommended in its place. There are limited data comparing aFT and cFT in clinical populations., Aim: The purpose of this study was to compare aFT with cFT in a population of ambulatory men in a clinical setting., Methods: Medical records were reviewed for 100 randomly selected men in a urology practice, yielding 140 test results complete for TT, aFT, and SHBG. Calculated FT was determined via an online calculator. Comparisons were made with Pearson rank coefficients., Main Outcome Measures: Pearson rank correlation between aFT and cFT., Results: Mean patient age was 52.3 +/- 14.3 years (range 24-80). Mean TT was 443.0 +/- 208.3 ng/dL (range 110-1276). Mean aFT was 1.22 +/- 0.54 ng/dL (range 0.24-3.8) and mean cFT 9.4 +/- 4.5 ng/dL (range 1.8-27.8). Mean SHBG was 34.2 +/- 19.5 nmol/L (range 9-127). A strong correlation was observed for aFT and cFT (r = 0.88, P < 0.0001), particularly at low concentrations. Significant correlations were also noted between aFT and TT (r = 0.73, P < 0.0001), and between cFT and TT (r = 0.82, P < 0.0001). Numerical values for aFT were approximately one-eighth of the values obtained for cFT. Neither aFT nor cFT correlated with SHBG., Conclusions: A strong correlation was observed between aFT and cFT in this clinical population of ambulatory men. Different sets of reference values must be applied for each of these tests.

Methyl tert-butyl ether (MTBE) is an oxygenated compound, which has been widely used in Asia, Europe and North America. Although numerous in vitro and in vivo studies have demonstrated the carcinogenicity and the toxicity of MTBE, there is still a lack of data on reproductive system exposure of MTBE in male rodent animals. We studied subacute exposure of MTBE on the reproductive systems of male Sprague-Dawley rats. MTBE was administered to rats at dose levels of 0, 400, 800 and 1600 mg/kg/day. After 2 or 4 weeks of treatments, the rats were euthanized, and their serum, epididymis and testes were collected. Significant adverse effects in their reproductive system were observed including: a significant increase in the percentage of abnormal sperm; an irregular and disordered arrangement of the seminiferous epithelium indicated by a histopathological examination; changed serum levels of testosterone (T), luteinizing hormone (LH) and follicle stimulating hormone (FSH); and decreased levels of mRNA and of androgen binding protein (ABP). In the oxidative stress study, results indicated an increased maleic dialdehyde (MDA) content, implying a raised peroxide level, and that the total antioxidant ability in serum was significantly increased. This finding was especially strong at 1600 mg/kg/day MTBE. In the 2-week treatment, at 1600 mg/kg/day, the mRNA level of 8-oxoguanine DNA glycosidase (OGG1) was significantly decreased, and the mRNA level of the extra-cellular form of superoxide dismutase (SOD(EX)) was significantly increased. Our experiments suggest that relatively high doses of MTBE can exert reproductive system toxicity of male rats and disturb the secretions of T, LH and FSH, possibly due to oxidative stress induced by MTBE.

In the sex hormone binding globulin (SHBG) gene, a pentanucleotide-repeat polymorphism [(TAAAA)(n)] and a single nucleotide polymorphism (D327N) have been associated with circulating SHBG concentrations in women. Only one study, limited to Scandinavians, has examined these associations in men. Using data from the Coronary Artery Risk Development in Young Adults (CARDIA) Male Hormone Study, the authors assessed associations of SHBG polymorphisms with serum SHBG levels in 511 Black men and 698 White men who had SHBG measured in multiple serum samples collected over an 8-year period from 1987 to 1996 and were aged 20-34 years at the time of the first SHBG measurement. Multivariable repeated-measures analyses were used to assess associations of (TAAAA)(n) and D327N polymorphisms with SHBG concentrations. Results showed statistically significant differences in mean SHBG concentrations for White men with genotypes of (TAAAA) 6/6 (35.1 nmol/liter), 6/x (30.8 nmol/liter), and x/x (29.6 nmol/liter), where x represents a repeat length greater than 6 (p = 0.001). For Black men, the pattern of association was similar, albeit not statistically significant (p = 0.35). There was no relation between D327N genotype and SHBG levels. These results suggest that the (TAAAA)(n) repeat length in the SHBG gene, but not the D327N variant, might contribute to the interindividual variability in serum SHBG levels.

Polychlorinated biphenyls (PCBs) are ubiquitous and persistent environmental contaminants that disturb normal endocrine functions including gonadal functions in humans and mammals. The present study was conducted to elucidate the protective role of vitamins C and E against Aroclor 1254-induced changes in Leydig cell steroidogenic acute regulatory (StAR) protein and steroidogenic enzymes mRNA expression. Adult male rats were dosed for 30 days with daily intraperitoneal (i.p.) injection of 2 mg/kg Aroclor 1254 or vehicle (corn oil). One group of rats was treated with vitamin C (100 mg/kg bw day) while the other group was treated with vitamin E (50 mg/kg bw day) orally, simultaneously with Aroclor 1254 for 30 days. One day after the last treatment, animals were euthanized and blood was collected for the assay of serum hormones such as luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone and estradiol. The serum androgen binding protein was also estimated. Testes were quickly removed and Leydig cells were isolated in aseptic condition. Purity of Leydig cells was determined by 3beta-hydroxysteroid dehydrogenase (3beta-HSD) staining methods. Purified Leydig cells were used for quantification of androgen and estrogen receptors. In addition, total RNA was isolated from control and treated Leydig cells to monitor the steady-state mRNA levels by RT-PCR for StAR protein, cytochrome P(450)scc, 3beta-HSD and 17beta-HSD. Aroclor 1254 treatment significantly reduced the serum LH, FSH, testosterone, estradiol and androgen binding protein. In addition to this, Leydig cell androgen and estrogen receptors were markedly decreased. RT-PCR analysis of StAR mRNA level did not alter Aroclor 1254 treatment while steroidogenic enzymes such as cytochrome P(450)scc, 3beta-HSD and 17beta-HSD mRNAs were drastically decreased in Aroclor 1254 treatment. However, the simultaneous administration of vitamins C or E in Aroclor 1254-exposed rats resulted a significant restoration of all the above-mentioned parameters to the control level. These observations suggest that vitamins C and E have ameliorative role against PCBs-induced testicular Leydig cells dysfunction.

While germ cell regulation of Sertoli cells has been extensively explored in adult rats in vivo, in contrast, very little is known about germ cell influence on Sertoli cell function at the time when spermatogenesis begins and develops. In the present study various Sertoli cell parameters (number, testicular androgen binding protein (ABP) and testin, serum inhibin-B and, indirectly, follicle-stimulating hormone (FSH)) were investigated after the exposure of 19-day-old rats to a low dose of 3 Grays of gamma-rays. Differentiated spermatogonia were the primary testicular targets of the gamma-rays, which resulted in progressive maturation depletion, sequentially and reversibly affecting all germ cell classes. Testicular weight declined to a nadir when pachytene spermatocytes and spermatids were depleted from the seminiferous epithelium and complete or near complete recovery of spermatogenesis and testicular weight was observed at the end of the experiment. Blood levels of FSH and ABP were normal during the first 11 days after irradiation, when spermatogonia and early spermatocytes were depleted. While the number of Sertoli cells was not significantly affected by the irradiation, from days 11-66 after gamma-irradiation, ABP production declined and FSH levels increased when pachytene spermatocytes and spermatids were depleted and the recovery of these parameters was only observed when spermatogenesis was fully restored. Comparison of the pattern of change in serum levels of inhibin-B and testicular levels of testin and of germ cell numbers strongly suggest a relationship between the disappearance of spermatocytes and spermatids from the seminiferous epithelium and the decrease in levels of inhibin-B and increase in levels of testin from 7 to 36 days post-irradiation. Levels of testin and inhibin-B were restored before spermatogenesis had totally returned to normal. In conclusion, this in vivo study shows that pre-pubertal Sertoli cell function is under the complex control of various germ cell classes. This control presents clear differences when compared with that previously observed in adult animals and depends on the Sertoli cell parameter of interest, as well as on the germ cell type.

Background: Male osteoporosis is often an underestimate and non-acknowledged pathology because it is less frequent then post-menopausal women osteoporosis. The causes of osteoporosis in males were reviewed, considering the importance of the assessment of sexual hormones, even without symptoms of hypogonadism., Methods: Sixty-two patients ranging in age from 45 to 75 years, males, were studied. None of them had assumed steroids nor other drugs causing osteoporosis. These patients have been subjected to bone mineral analysis (BMA) together with the following sexual hormones: LH, FSH, total testosterone, free testosterone, SHBG, estrone, estradiol. Two methods of BMA have been employed (Norland 2780 and UBA 575 Walker and Sonix)., Results: When osteoporosis or osteopenia were present, always there were modifications of sex hormones values. Statistic evaluation (linear regression, Pearson coefficient, Multiple regression, Backward Stepwise Multiple Regression), showed that there was a significant association between total testosterone and osteoporosis., Conclusions: Total testosterone resulted the most predictive sex hormone for the loss of bone mass; therefore, it is important to evaluate sex hormones in males with osteoporosis, for a correct and "physiological" therapy.

The impact of neonatal onset hypothyroidism from day 1 postpartum through different postnatal developmental events on rat testis was studied in vivo. Hypothyroidism was induced in neonates by feeding the lactating mother or directly with 0.05% methimazole (MMI) through drinking water from the day of birth and were killed at day 10, 15, 30, 40 and 60 postpartum. Hypothyroidism was confirmed by radioimmunoassay of thyroid hormones and TSH. Sertoli cell number, plasma and testicular interstitial fluid (TIF) androgen binding protein (ABP) concentration was quantified. Sertoli cell number was consistently decreased in all hypothyroid rats. Plasma ABP was also decreased irrespective of the duration of hypothyroidism. Unlike plasma ABP, TIF ABP concentration in hypothyroid rats increased at day 10, and 15 postpartum and decreased in other age groups. Plasma FSH level was increased significantly in all hypothyroid groups. The present investigation points out that suppression of T3 during the critical period of Sertoli cell proliferation affects their number and functional activity.

The impact of transient neonatal hypothyroidism on growth and function of puberal testis during different milestones of postnatal testicular development was studied in Wistar rats. Rat pups were made hypothyroid for 10, 15, 30, 40 and 60 days of postnatal age from birth by providing 0.05% (W/V) methimazole (MMI) in the drinking water of the mother, from day 1 postpartum till weaning (25 days postpartum) and thereafter in the drinking water. Control rats were raised without MMI treatment. Sertoli cell number and its function was assessed on day 60 postpartum. Sertoli cell number increased consistently in 10, 15, 30 and 40 days transient hypothyroid rats but decreased in rats subjected to continuous hypothyroidism from birth to 60 days postpartum. Rats subjected to continuous hypothyroidism from birth showed spermatogenic arrest at puberty and had only a single layer of spermatogonia. Transient neonatal hypothyroidism for 10 (or) 15 days from birth increased spermatocytes (pachytene and zygotene), spermatids (elongated and round) whereas, that of 30 and 40 days decreases the number of germ cells. Plasma androgen binding protein (ABP) concentration decreased in puberal rats belonging to all groups, whereas the testicular interstitial fluid (TIF) concentration of ABP increased significantly in 10 and 15 days hypothyroid rats while it decreased in all other groups. These findings indicate that the mitogenic activity of Sertoli cell is increased irrespective of the duration of transient neonatal hypothyroidism. However, the functional activity of Sertoli cells (ABP production) in these puberal rats varies depending upon the postnatal period at which the animals were in hypothyroid state.

Purpose: To study the effects of antiepileptic drugs (AEDs) on sex hormone levels and sexual activity in a group of men attending a hospital-based epilepsy clinic., Methods: One hundred eighteen men being treated with AED therapy, 32 with epilepsy but not receiving AEDs, and 34 controls were recruited. All subjects were aged 18-65 years. Blood (20 ml) was removed for hormone assays, after which each subject completed a validated questionnaire [Sexuality Experience Scores (Frenken and Vennix, 1981)] aimed at exploring the individuals' sexual activity and attitudes to sexual morality., Results: Men taking carbamazepine (CBZ) only had significantly higher mean sex hormone-binding globulin (SHBG) levels than the control group. The CBZ group also had a significantly lower mean DHEAS concentration than the control, untreated, and sodium valproate (VPA) monotherapy groups. The phenytoin monotherapy group (PHT) had a significantly higher mean SHBG than both the control and untreated groups, and had a significantly higher mean total testosterone (TT) value than the control untreated, CBZ, and VPA groups, and a significantly lower mean DHEAS than the controls, untreated, and VPA groups. Men receiving more than one AED had significantly higher mean SHBG concentrations compared with control, untreated, and VPA groups. In addition, the polytherapy group's mean TT was significantly higher than the control and VPA groups, although its mean DHEAS concentration was lower than the control, untreated, and VPA groups. There were no significant differences between the study groups in mean FT, Budrostenedione (AND), or estradiol levels. But the CBZ, PHT, and polytherapy groups had significantly lower mean free and rogen index (FAI) than the controls. The CBZ group had a lower mean FAI than the VPA group. The polytherapy group had a lower FAI than the untreated group. Sexuality Experience Scores (SES) showed that those men receiving AEDs embraced a stricter sexual morality than the controls and untreated, and expressed greater satisfaction with their marriages than the control and untreated groups., Conclusions: Seizure type did not affect SES scores. Multiple regression showed men who had received further education were less accepting of strict sexual morality.

Serum androgen-binding capacity in Djungarian hamsters, as in many other mammals, increases within days after birth and remains elevated until puberty. This increased activity has been attributed to a hepatic glycoprotein, sex hormone-binding globulin (SHBG), but expression of SHBG by the postnatal liver has not been demonstrated. Therefore, a full-length SHBG cDNA was cloned from the liver of neonatal hamsters and the expression of SHBG during development was examined. Hepatic SHBG RNA levels, as measured by both competitive RT-PCR and Northern analysis, were very low in fetal animals but increased significantly within 24 h of birth. Maximal values were maintained for 1 week after parturition, and then declined to basal adult levels. The developmental pattern in hepatic SHBG immunoactivity, as determined by Western analysis, mirrored that of hepatic SHBG mRNA. However, changes in serum SHBG immunoactivity and steroid-binding activity occurred approximately 1 week later. There were no sex differences in the levels of hepatic SHBG mRNA or protein during development, but serum immunoactivity tended to be higher in females at puberty. Sex- and age-related differences in the relative abundance of SHBG isoforms were also noted. Results of these studies demonstrate that Djungarian hamsters express an authentic SHBG and indicate that the postnatal surge in serum androgen-binding activity is due to perinatal up-regulation of SHBG expression.

The effects of gonadotropins and gonadal steroids on androgen-binding protein (ABP) production and its distribution among the epididymis, seminiferous tubule fluid (STF), testicular interstitial fluid (TIF), and blood were studied in 300-g adult male Sprague-Dawley rats. The rats either received no treatment or their pituitary function was suppressed by administration of the GnRH antagonist [AcD2Nal,D4ClDPhe2,D3Pal3,Arg5,DGlu6 (AA),D-Ala10]LHRH (antagonist). Other groups of rats were treated with hCG, FSH, FSH plus hCG, testosterone, or estradiol, alone or together with antagonist. Treatment was conducted for 30 days, after which time, ABP was detected by its ability to bind [3H]5 alpha-dihydrotestosterone. Transport of ABP from the testis to the epididymis was inhibited by antagonist administration. Simultaneous treatment with antagonist and hCG, or antagonist and hCG plus FSH prevented antagonist-induced inhibition of ABP transport. Neither FSH, testosterone, nor estradiol alone was effective in this process. Inhibition of ABP transport to the epididymis was accompanied by its accumulation within the testis. Treatment with antagonist and FSH resulted in a 4.5-fold increase in the concentration of ABP in TIF, but had little effect on the amount of ABP in STF, indicating selective secretion of ABP from the basal surface of the Sertoli cells. Treatment with antagonist alone, antagonist together with testosterone or estradiol, or estradiol alone resulted in increased concentrations of ABP in both TIF and STF, but the increase in TIF was proportionately greater. Treatment with hCG or FSH plus hCG alone or with antagonist not only facilitated ABP transport to the epididymis, but also increased TIF levels of ABP above control values. The former treatment resulted in increased concentrations of testosterone in TIF, but not in STF. Both treatments resulted in testosterone levels in both compartments that were higher than those in animals treated with antagonist alone. No treatment had a statistically significant effect on blood levels of ABP. About 50% of ABP synthesis appears to be constitutive, i.e. is not regulated by hormones. Although ABP production continues in the presence of antagonist, its transport to the epididymis is halted, indicating that epididymal transport of ABP is a hormone-dependent process. It is likely that elevated intratesticular levels of testosterone or FSH and testosterone acting in concert regulate epididymal transport of ABP.

In contrast to women, fertility in men persists until a very old age. However, testicular function of both the exo- and endocrine compartments decreases in old age, causing a series of clinical symptoms which are analogous to, although less pronounced than, the menopausal syndrome. These symptoms can be considered to represent the male climacterium or andropause. However, whereas at menopause ovarian hormonal secretion ceases almost completely, the decrease in the levels of biologically active endrogens (free testosterone) is only moderate and many elderly men have free androgen levels that would be considered normal for young men. Moreover, whereas many well-controlled studies have shown the benefit of hormonal replacement therapy, at least for symptomatic posmenopausal women, so far no well-controlled studies exist that prove a favourable risk/benefit balance of androgen substitution in elderly men. The major risk is the potentially stimulating effect of androgens in elderly men who frequently present with subclinical prostatic carcinoma. Therefore, the generalized use of androgen substitution in elderly men cannot, as yet, be recommended.

In 82 females with hyperandrogenism and polycystic ovaries, the sensitivity and diagnostic accuracy of the free-androgen index (FAI) were compared with those of testosterone (T), free testosterone (fT), androstenedione (A), LH and the LH/FSH ratio. Normal ranges for each parameter were derived as 95th percentile in 53 healthy controls of similar age. T, fT, A, FAI, LH and LH/FSH were significantly (p < 0.001) higher in patients than controls. The sensitivity and diagnostic accuracy of the FAI (0.46 and 0.64) were lower than those of T (0.67 and 0.78) and A (0.56 and 0.73) and similar to those of fT and LH/FSH. The overall variance of the FAI was highest among all parameters. The FAI was significantly (p = 0.05) elevated in a subgroup with obesity (n = 34), whereas T and fT did not differ in obese and nonobese subjects with polycystic-ovary syndrome. We cannot recommend the routine measurement of the FAI in the rational laboratory evaluation of female hyperandrogenism for the following reasons. (1) The adequate normal range for the FAI (< 8.7) is substantially higher than previously thought in normal individuals, which has serious consequences for the accuracy of the test. (2) The values of the FAI showed the widest overlap with controls. (3) The significant positive correlation between FAI and fT allows the prediction of the FAI from the measurement of fT, rendering the determination of a second parameter for the free bioactive T unnecessary. (4) The FAI as well as sex-hormone-binding globulin are influenced by body weight, whereas T and fT are markers for hyperandrogenism independent of obesity.

This study examines the effects of a potent gonadotropin releasing hormone (GnRH)-antagonist (GnRH-A, Ac-D[2] Nal1, 4-CL-D Phe2, D-Trp3, D-Arg6, D-Ala10) upon the distribution of androgen binding protein (ABP) in serum, testis, and epididymis, and its relationship with the completion of spermatogenesis in Sprague-Dawley rats. After 2 weeks of daily injections of 10 micrograms/kg, 50 micrograms/kg, 100 micrograms/kg, or 500 micrograms/kg of GnRH-A, testicular ABP content was either unchanged or elevated (P less than 0.05), and serum ABP levels were elevated (P less than 0.01). Spermatogenesis was maintained in animals administered 10 micrograms/kg or 50 micrograms/kg GnRH-A, and epididymal ABP content remained unchanged. On the other hand, daily injections of 100 micrograms/kg or 500 micrograms/kg GnRH-A resulted in a significant decrease in epididymal ABP content (P less than 0.05), and spermatogenesis was arrested at early spermiogenesis. After 4 weeks of GnRH-A administration, both testicular and epididymal ABP were decreased in a dose-dependent manner in animals receiving doses of 50 micrograms/kg or higher of GnRH-A. In order to evaluate the normalcy of the bidirectional release of ABP in GnRH-A treated rats, additional rats were given daily injections of 25 micrograms/kg or 250 micrograms/kg of GnRH-A for 2 weeks. Concentrations of ABP in interstitial fluid (ITF) and seminiferous tubular fluid (STF) remained unchanged, but serum ABP levels were significantly increased (P less than 0.05) in rats administered 25 micrograms/kg GnRH-A. Qualitatively normal spermatogenesis was maintained and epididymal ABP content did not differ from that of control animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Testicular growth is depressed in the genetically sterile male rat (hd/hd) relative to its LE phenotype littermates (by 50% and 73% at 27 and 90 days of age, respectively). Within the hd/hd testis, both the tubular and seminiferous tubule tissues are affected by the mutation. In addition, there is significantly less germ cell production from the primary spermatocyte stage of spermatogenesis onwards and the total number of Sertoli cells observed is less. In the intertubular tissue, the total volume and the total number of Leydig cells per testis is significantly less, but the mean volume of an average Leydig cell is not modified. The serum gonadotropin levels are higher in the hd/hd rat, whereas from 40 days of age onwards the level of testosterone is lower. The FSH and LH binding affinity constants are unchanged by the mutation; however, the total number of FSH binding sites per 10(6) Sertoli cells is lower while that of LH per 10(6) Leydig cells is greater. Indeed, it is likely that the lesser concentration of serum testosterone in the hd/hd rat is a result of a smaller number of Leydig cells since their individual function is not modified. The testicular androgen binding protein (ABP) content and the ABP output towards the epididymis are lower as a consequence of both a lesser number and an altered function of the Sertoli cells.(ABSTRACT TRUNCATED AT 250 WORDS)

The present study examined the relationship between the functional status of Sertoli cells and the maintenance and restoration of spermatogenesis in immature hypophysectomized (HPX) rats given various doses of exogenous testosterone with or without daily injections of FSH for 90 days. Subcutaneous implantation of a 2- to 10-cm testosterone capsule (TC) increased serum testosterone levels of HPX rats 2-10 times above the normal control levels, but did not significantly increase the testicular testosterone level. Daily injections of FSH significantly increased the accumulation of testosterone in testes of TC-implanted HPX rats. Maintenance of early spermiogenesis was observed in all TC-implanted animals. Although elongated spermatids were present, step 18-19 spermatids at the luminal edge of stages VII-VIII epithelium were only observed in rats bearing 10-cm TC implants. Daily injection of FSH resulted in the completion of spermiogenesis in all TC-implanted animals, and the number of step 18-19 spermatids was dependent on the length of TC implants used. These results demonstrate the importance of the synergism of FSH and testosterone in the final steps of spermiogenesis. The androgen-binding protein (ABP) content per testis of the HPX rats was stimulated by TC implants. However, a significant increase in epididymal ABP was only noted in rats bearing 10-cm TC implants. Injection of FSH resulted in a significant increase in the testicular ABP content in rats bearing 2- or 5-cm TC, but not in those with 10-cm TC implants. In addition, the epididymal ABP content was significantly stimulated by FSH in all TC-implanted animals. The ABP status in the testis and its transport toward the epididymis are closely related to the extent of maintenance of spermiogenesis. It is speculated that the production of ABP by Sertoli cells and the biochemical properties of ABP molecules may have some role in the control of the final steps of spermiogenesis.

Boric acid is an inorganic acid that impairs fertility in male rodents. A reproductive assessment by continuous breeding study found that male rats treated with boric acid had decreased fertility and sperm motility. In order to determine the cell type that is first affected by boric acid, we have examined the development of the boric acid-induced testicular lesion by light and electron microscopy. Adult F344 male rats were fed 9000 ppm boric acid in NIH-07 rat chow for up to 4 weeks. The first testicular lesion noted was an inhibition of spermiation, which appeared by Day 7. Widespread exfoliation of apparently viable germ cells, and pachytene cell death in stages VII and XIV, appeared as exposure continued. After 28 days of dosing, extreme epithelial disorganization and germ cell loss were evident. To determine if there was a hormonal component to the boric acid-induced testicular lesion, serum levels of basal, hCG-, and LHRH-stimulated testosterone levels were measured. After 4 days of dosing, basal testosterone levels were lower than controls and remained low during dosing. However, serum testosterone levels were similar in both boric acid-treated and control animals after either hCG or LHRH challenge. To determine if boron was preferentially accumulated by the testis, boron levels in testis, epididymis, liver, kidney, and blood were measured. Boron levels had effectively reached steady-state levels by Day 4 and were not differentially concentrated in the tissues examined. Thus, these studies characterize the testicular lesion produced by boric acid exposure and identify a decrease in basal serum testosterone levels in the absence of selective accumulation of boron in the testis.

To identify the factor(s) involved in the decreased of sex steroid binding-protein (SBP) in hirsute women, we have investigated which parameters were in correlation with SBP in a population of 90 hirsute women. We found no significant correlation of SBP binding capacity with the plasma concentrations of the main androgens. Conversely, SBP was in inverse and significant correlation with body mass index and with the fasting insulin plasma level. These findings confirm that nutritional status must be considered in the physiopathology of hyperandrogenism in women. The control of overweight may be a goal for treating hirsutism in some patients.

We examined the hypothesis that induction of reversible testicular atrophy, subsequent to withdrawal of gonadotrophin support, would alleviate the testicular toxicity of the anti-cancer drug procarbazine. In rats, severe but reversible testicular atrophy and suppression of spermatogenesis were induced 56 days after the subcutaneous insertion of a silastic implant containing oestradiol-17 beta. The effect of this treatment upon the testicular toxicity of four weekly doses of procarbazine (200 mg kg-1) was examined 56 days after the termination of procarbazine/oestrogen treatment. At this time the testicular endocrine and spermatogenic functions were close to normal in rats which has received only oestradiol-17 beta. Procarbazine produced severe testicular atrophy which was associated with azoospermia and destruction of the germinal epithelium. Serum LH and FSH concentrations were raised and were associated with low serum concentrations of both testosterone and androgen-binding protein. The combination of procarbazine with the oestrogen treatment did not change any of the testicular toxicity and in some cases it appeared to be exacerbated. In contrast to these experiments other studies have indicated that the testis can be protected if spermatogenesis is reversibly suppressed by other agents which are also active via the pituitary endocrine system. The data would therefore suggest that protection is achieved either by some testicular change other than withdrawal of pituitary gonadotrophin support or that oestradiol-17 beta has additional activity which is permissive for the development of the testicular toxicity of procarbazine.

The binding of sex steroids to plasma proteins was examined in post-natal Djungarian and golden hamsters. With dihydrotestosterone or testosterone as ligands, steady-state polyacrylamide gel electrophoresis revealed 2 androgen binding components in the plasma of young Djungarian hamsters of both sexes. The fast-moving component exhibited a low affinity and high capacity for androgens and corresponded to albumin in stained gels. In contrast, the slow moving component was a beta-globulin with high affinity (Ka = 10(9) M-1) and low capacity for androgens, and was identified as a specific sex steroid-binding protein (SBP; also SHBG). This SBP did not bind oestrogens or corticosteroids and was electrophoretically distinct from corticosteroid-binding globulin (CBG). In addition, this protein did not appear to be of testicular origin because it was present in immature females and in immature males that had been castrated for 8 days. Plasma concentrations of SBP in males as measured by a diethyl-aminoethyl-cellulose binding assay were low at birth, became significantly elevated shortly thereafter when plasma androgen values were also elevated, and subsequently fell to low levels during puberty. These changes follow the same general pattern that has been described for other mammals, including humans, during this period of reproductive development. Although the significance of elevated SBP concentrations during prepuberty has yet to be determined, it appears that the increased concentrations of high-affinity androgen binding in the plasma of Djungarian hamsters plays a role in the asynchronous pubertal development of the testes and accessory organs which occurs in this species. The post-natal SBP pattern in females was similar to that observed in males. Plasma SBP levels were low or undetectable in adults of both sexes. As previously described for adult golden hamsters, the plasma of post-natal male and female golden hamsters lacked a specific SBP: androgen binding in this species is apparently limited to albumin and CBG.

In order to obtain comparative analysis between the steroid binding proteins from blood serum and seminal plasma, fresh samples were incubated and assayed in parallel with the following tritiated steroids: dihydrotestosterone, testosterone, cortisol, progesterone and estradiol. Thereafter, and using techniques such as (1) polyacrilamide disk gel electrophoresis with elution of proteins from the gel slices, (2) ammonium sulphate precipitation, (3) enzymatic hydrolysis, and (4) gel filtration on Sephadex G-100, there was a resemblance in the electrophoretic patterns confirming the presence in both fluids of proteins like TeBG, CBG, and Albumin, previously described in blood serum. In seminal fluid, but not in blood serum, another small protein with androgen binding capacity was found and its preliminary characterization demonstrated: disappearance with enzymatic treatment, low molecular weight, negative charge, and precipitation range with ammonium sulphate from 30 to 35%. Its elution profile on Sephadex G-100 was contaminated with albumin.

The dose- and time-related responses of the irradiated seminiferous epithelium in the pubertal rat have been investigated. The threshold dose for Sertoli cell dysfunction, as assessed by serum androgen binding protein (ABP) concentrations, was estimated to be 5 Gy. A significant reduction (to less than 50% of control levels) in serum ABP was observed at 8 weeks post-irradiation, with further reductions at later times (24 and 36 weeks). Serum follicle-stimulating hormone (FSH) was elevated to between 130 and 175% of control at only 2 weeks post-irradiation, but recovered with time. Normal FSH levels seemed to be related to recovery of spermatogenesis, as assessed by counts of regenerating tubule cross-sections. The results indicate that the clonogenic spermatogonia and Sertoli cells of the pubertal rat testis are less sensitive to radiation than those of the adult.

To investigate the relationship between free testosterone and sexual maturation in the male rat, animals were decapitated every 5 days from 25 through 75 days of life. Serum was assayed for androgen binding protein and total testosterone by radioimmunoassay. Free testosterone concentrations were calculated from the total testosterone concentration and the free testosterone fraction. The free testosterone fraction was determined by ultrafiltration. The pubertal increase in relative prostate and relative seminal vesicle weights began between 45 and 50 days and 40 and 45 days, respectively. Although the over-all trend in the free testosterone fraction was to increase with increasing age (r = 0.46, P less than 0.0001), there was a significant secondary peak at 50 days. The serum concentration of androgen binding protein was highest on day 25, fell rapidly until day 40, and declined slowly thereafter. Despite these variations in both androgen binding protein and the free testosterone fraction during sexual maturation, the calculated serum concentration of free testosterone was remarkably similar in pattern to that of total testosterone (r = 0.99, P less than 0.0001). These data indicate that the serum concentration of total testosterone is an accurate reflection of the serum concentration of free testosterone during the sexual maturation of the male rat.

beta-Endorphin and other peptides derived from proopiomelanocortin are synthesized in testicular Leydig cells. To better understand the possible function of these and other endogenous opioid peptides in the testis, the opioid antagonists naloxone and nalmefene were administered intratesticularly to hemicastrated 5-day-old rats. Both naloxone and nalmefene potentiated testicular hypertrophy induced by unilateral orchidectomy at 11 days of age. Unexpectedly, at least a 100-fold lower dose of nalmefene was required to produce maximal hypertrophy than that previously reported for naloxone. Leydig and Sertoli cell functions were evaluated, respectively, by measurement of basal testosterone production in vitro and rat androgen-binding protein (rABP) in serum. The optimal dose of naloxone for hypertrophy (1 microgram/testis) suppressed testosterone production and had a nonuniform effect on rABP secretion (either had no effect or produced a slight increase). By contrast, the optimal dose of nalmefene for hypertrophy (0.01 microgram/testis) not only suppressed basal testosterone secretion, but also uniformly increased rABP levels in serum. Larger doses of this opioid antagonist, up to 1 microgram/testis, were not as effective on the three parameters measured (hypertrophy, testosterone secretion, and rABP levels). These results suggest that this agent has both antagonistic and agonistic activities in the testis. At the doses that produced optimal effects on hypertrophy, systemic administration of these antagonists produced no effects. The results of these studies suggest that intratesticular opiates exert a suppressive effect on Sertoli cell growth and rABP secretion. In addition, these peptides may modulate testosterone secretion by Leydig cells.

FSH binding and cAMP responses to FSH in Sertoli cell-enriched testes were not affected by the vitamin A (retinol) status of the animals. These results indicate that changes in Sertoli cell functions during vitamin A deficiency are independent of FSH-Sertoli cell interactions. Concentrations of serum androgen binding protein (ABP) in vitamin A-deficient rats were consistently higher than those of control animals throughout the study period. The accumulation of testicular fluid after efferent duct ligation, an indication of Sertoli cell secretory function, was normal in vitamin A-deficient rats at least until 70 days of age, but declined thereafter. ABP concentrations in seminiferous tubular fluid of vitamin A-deficient rats increased transitorily during the 70-80-day age period but returned to normal by 90 days. The increment of ABP in seminiferous tubular fluid after efferent duct ligation, and ABP concentrations in interstitial fluid were consistently lower in vitamin A-deficient rats. The higher serum ABP in vitamin A-deficient rats therefore cannot be explained by an increase in the permeability of Sertoli-cell tight junctions or basement membrane.

While the general toxicity of the benzimidazole pesticides for mammals is low, one of these compounds, carbendazim (MBC), causes degeneration of testicular tissue and decreases spermatogenic activity at doses well below the LD50 value. A study conducted by S. D. Carter, R. A. Hess, and J. W. Laskey (1987, Biol. Reprod. 37, 709-717) showed that treatment with 400 mg/kg/day MBC resulted in severe seminiferous tubular atrophy and infertility. Since spermatogenesis is an androgen-dependent process, we characterized the effects of MBC (0-400 mg/kg/day) on the endocrine function of the rat testes. Following subchronic (85 day) exposure, serum hormones (TSH, LH, FSH, and Prl) were measured as were androgen binding protein (ABP) and testosterone in testicular fluids (interstitial fluid and seminiferous tubule fluid). In addition, the functional capacity of the Leydig cell to secrete testosterone was assessed in vitro following an hCG challenge. Subchronic treatment with MBC at doses of 50-100 mg/kg/day had no effect on pituitary or testicular hormone concentrations: 200 mg/kg/day elevated the testosterone concentration in the seminiferous tubule fluid and the ABP concentration in both the interstitial fluid and the seminiferous tubule fluid without affecting serum testosterone or ABP concentrations. The 400 mg/kg/day dose resulted in increased concentration of both testosterone and ABP in the interstitial fluid and seminiferous tubule fluid and elevated serum ABP, with no change in serum testosterone. This endocrine profile is consistent with the testicular atrophy and "Sertoli cell-only" syndrome seen in these animals as reported by Gray et al. (1987, Toxicologist 7, 717). We conclude that seminiferous tubule fluid testosterone may be a result of two factors: (1) increased interstitial fluid testosterone concentrations and (2) decreased testosterone outflow from the testis to the general circulation. Also, increased ABP in the interstitial fluid may reflect a change in the relative secretion of ABP into the interstitial fluid and the seminiferous tubules.

beta-Endorphin is believed to be synthesized in testicular Leydig cells. To gain more information about the role of this and other endogenous opioid peptides in the testis, opiate antagonists (naloxone and nalmefene, 100 micrograms/testis) were administered intratesticularly to hemicastrated adult rats. Leydig cell function was evaluated by measurement of serum testosterone and testosterone production in vitro. Estimation of androgen binding protein (rABP) was used as an index of Sertoli cell function. Serum testosterone was reduced significantly by intratesticular administration of naloxone and nalmefene in treated animals. Systemic administration of these antagonists had no effect at the doses used. Testes from treated animals incubated in vitro with or without hCG produced significantly less testosterone than vehicle-treated control testes. Hemicastration reduced rABP synthesis and secretion; however, treatment with opiate antagonists did not alter the amount of this protein in the serum or epididymides of these rats. These observations suggest that endogenous testicular opiates modulate testosterone secretion by Leydig cells.

In the rat, the effects of progestin and androgen administration on serum, testicular and epididymal androgen binding protein (rABP) concentrations were determined and related to the organ weight and morphology. Adult rats were treated with medroxyprogesterone acetate (MPA; 17 alpha-acetoxy-6 alpha-methylprogesterone), testosterone propionate (TP) and mibolerone (MB; 7 alpha, 17 alpha-dimethyl-19-nortestosterone). MPA reduced testicular and epididymal weights and the concentrations of serum follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone. During MPA treatment testicular and epididymal ABP content declined in parallel with organ weights and hormone concentrations, whereas serum ABP concentrations increased. Combinations of MPA and TP reduced testicular and epididymal ABP, but the reductions were less than with MPA alone; this combined treatment also elevated serum AMP. Both MB and TP reduced ABP in the male reproductive tract, but unlike MPA did not increase the concentration of this protein in serum. The results suggest that MPA acts directly on Sertoli cells resulting in increased ABP release into the blood. The comparison was made of steady state polyacrylamide gel electrophoresis (SS-PAGE) and radioimmunoassay (RIA) methods of estimating rABP. The potency ratio of testicular ABP estimated by the two methods (RIA:SS-PAGE) was three times higher than this ratio in the epididymis in normal and hormonally treated animals. Due to differences in end points, these observations imply that these assays do not quantify the molecules in the same way in one or both of these tissues. The results indicate, however, that both assays are suitable for following rABP concentration in animals with altered hormonal states.

We were interested in discovering whether the antifertility agent, DICA [1-(2,4-dichlorobenzyl)-1-H-indazole-3-carboxylic acid] induced Sertoli cell tight junction damage. Testis were fixed in 1% lanthanum nitrite cacodylate-buffered 2% gluteraldehyde at various times following a single oral 100 mg/kg dose of DICA. In control animals adluminal lanthanum was never seen. At one and ten days following DICA treatment adluminal lanthanum was seen. This suggests that the Sertoli cell tight junctions are more permeable to lanthanum following DICA treatment.

Androgen binding protein (ABP) was measured in the serum, testes and epididymides of adult male rats after treatment with ethylene dimethanesulphonate (EDS), which has direct cytotoxic effects on Leydig cells and secondarily affects sperm production. Serum ABP increased to a maximum 7 days after treatment and remained elevated for most of the 63 days of observation. The ABP content of both the epididymides and testes declined and were low between 14 days and 21 days following treatment. By contrast, the concentration of ABP in these tissues was maintained after EDS treatment and was sometimes elevated. This divergence between ABP content and concentration was due to atrophy of the testes and epididymides after the decline in androgen secretion. The changes in serum and tissue ABP levels after EDS occurred earlier than those observed in adult hypophysectomized animals, possibly due to local paracrine influences that are lost secondarily to destruction of the Leydig cells. Testicular testosterone did not parallel ABP content as it fell dramatically 2 days after EDS and remained low for about 21 days before returning to near control values after 63 days. Testicular and epididymal sperm heads decreased in number after EDS, but were not clearly associated with the changes in ABP. The results confirm that androgens are important for the production of ABP and for the partitioning of this protein between the blood and the lumen of the reproductive tract.

The present study was undertaken to determine if prior administration of zinc acetate (ZnAc) or copper sulfate (CuSO4) could prevent pituitary, Leydig, or Sertoli cell dysfunction subsequent to cisplatin administration in adult Sprague-Dawley rats. Animals were given cisplatin at a dose of 2 mg/kg daily for 5 days, with or without the i.p. administration of ZnAc (6 mg/kg per day) or CuSO4 (5 mg/kg per day), beginning 5 days prior to and continuing through the administration of cisplatin. Control animals were given vehicle, ZnAc1, or CuSO4. Animals were sacrificed 1 week after the initial cisplatin injection. Cisplatin administration resulted in suppressed serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels as well as a 77% reduction in serum testosterone and an 82% reduction in testicular testosterone. The concomitant administration of either ZnAc or CuSO4 did not result in a significant difference relative to animals receiving cisplatin alone, although administration of both cations alone significantly reduced testicular testosterone content. Serum androgen-binding protein (ABP) was not significantly lowered in any treatment group. There was a marked reduction of 57% in testicular ABP content relative to control values subsequent to cisplatin administration. This reduction was partially prevented by ZnAc treatment: the testicular ABP concentration was only 15% lower than that in controls (not significant). Since the cisplatin-induced reduction in serum FSH was not altered by ZnAc pretreatment, we conclude that the near normalization of testicular ABP content may be evidence of improved Sertoli cell function. In contrast, cisplatin-induced decreases in the serum gonadotropins and testicular androgens were not lessened by pretreatment with either cation. Further studies may be warranted to determine whether ZnAc pretreatment has a beneficial effect on spermatogenesis during cisplatin treatment.

Androgen binding protein (ABP) was measured in the serum, testes and epididymides of adult rats up to 105 days after the induction of reversible impairment of spermatogenesis by a single injection of busulphan. This treatment decreased testicular and epididymal weights within 7-21 days after treatment, reaching a minimum at 63 days with partial recovery by 105 days. The testicular and epididymal content of sperm was unchanged up to 42 days after busulphan administration, was reduced considerably at 63 days and thereafter increased towards control values. The serum and testicular concentrations of testosterone were normal at all times after treatment, even though serum LH levels were increased at 42 and 63 days. Serum levels of FSH were also increased at 43 and 63 days after treatment. A biphasic pattern in the serum levels of ABP was observed. Concentrations were low up to 43 days post treatment when only the early germ cell types were depleted from the seminiferous epithelium and when the testicular and epididymal contents of ABP were normal. Serum levels of ABP increased as the more mature germ cells were depleted in numbers and the testicular and epididymal contents of ABP declined. It is concluded that bidirectional secretion of ABP into the interstitium (serum) and into the seminiferous tubular lumen by Sertoli cells is influenced considerably by the population of germ cells that are present in the seminiferous epithelium.

The effects of hyperprolactinemia on testicular structure and pituitary-gonadal function were investigated in male rats. Hyperprolactinemia was induced in the Wistar-Furth rat by implantation of tissue fragments of a prolactin-secreting MtTW15 pituitary adenoma. The MtTW15 tissue was maintained in one animal group for 27 days (group A) and in another group for 37 days (group B). Appropriate age-matched controls were utilized in each study. Serum prolactin was significantly elevated (P less than 0.001) in both groups of MtTW15-bearing rats compared with their controls. The degree of hyperprolactinemia was more severe in rats of group B (2842 +/- 546 ng/ml) than in rats of group A (367 +/- 38 ng/ml). Accessory sex organ weights in group B rats were significantly lower than in controls, but were apparently unaffected in group A rats. Hyperprolactinemia induced definite but variable testicular alterations in both animal groups that presented as seminiferous epithelial disorganization, germ cell exfoliation, increased tubule wall thickness, and abnormal Leydig cell lipid content. Electron microscopy revealed structural disruption of Sertoli-germ cell junctional complexes and apical Sertoli cell cytoplasmic degeneration. The hyperprolactinemic rat exhibited significant reductions in serum luteinizing hormone (LH), testosterone (T), and androgen binding protein (ABP) when compared with controls. Eighty-six days following surgical removal of the MtTW15 tissue in a subgroup of group B rats, serum levels of prolactin and LH returned to normal, as did weights of accessory sex organs and testicular morphology. These results indicate that exposure to the MtTW15 adenoma and its later removal in the rat provides a workable model for studying the effects of hyperprolactinemia on testicular structure and function, and for identifying events involved in the subsequent recovery of spermatogenic disruption.

The present study examined the quantitative and qualitative effects of suppressed testicular testosterone concentration upon spermatogenesis. Adult male rats were given sc implants of 0.5- to 5-cm long testosterone filled silastic capsules (TC) for 10 weeks. Testicular testosterone concentrations were suppressed to below 5% of the control level in rats receiving 1.5- to 5-cm TC implants. Spermatogenesis was arrested at early spermatids in rats given 1.5-cm TC implants, but was maintained in those given 3- or 5-cm TC implants. The number of A1 spermatogonia was 10-15% higher in rats bearing 0.75- to 1.5-cm TC implants, while a 5-15% reduction in preleptotene spermatocytes was noted in rats receiving 1.5-cm or longer TC implants. Linear regression analysis revealed a significant negative correlation between the number of A1 spermatogonia and the percent yield of preleptotene spermatocytes. This result illustrates the presence of a negative feedback mechanism in the regulation of A1 spermatogonia. The lack of a correlation between the quantitative changes in germ cell number and the hormonal states suggests that factors or local mechanisms independent of the concentration of hormones are involved in the regulation of germ cell differentiation.

Fractionation of testicular, epididymal, and serum extracts containing rat androgen-binding protein (rABP) on a Concanavalin A-Sepharose (Con A) column resolved two peaks of immunoreactive protein. The first peak was present in the void volume, and the other was bound by the column and specifically eluted by alpha-methyl-D-glucoside. These two peaks of immunoreactive rABP have been designated form I and form II for the portions of rABP that do not and do bind, respectively, to Concanavalin A. In the course of studying this heterogeneity, we observed that the distribution of the two forms of rABP was the same in the blood and cytosols prepared from testis and epididymis of young rats before the formation of the blood-testis barrier; that is, the ratio of form I to form II ranged from 1:1 to 1:2. Similar heterogeneity was observed in extracts of the reproductive tract from mature animals. However, the blood of adult rats contained reduced amounts of form I relative to form II, so that their ratio was about 1:5. Subsequent studies of infertile rats heterozygous for the Hre gene (Hre/ +), in which total rABP secretion was decreased, and of their normal littermates, indicated that the reduced amount of form I ABP in the sera of mature rats is typical of adult animals regardless of strain or genetic abnormality. The reduced amount of form I relative to form II observed in the blood of adult rats could result from either reduced secretion or increased metabolic clearance of form I in the blood compartment. To distinguish between these possibilities, the blood clearance of the two forms was estimated after orchiectomy. The disappearance rate of form I was not significantly different from that of either form II or unfractionated serum. These results are consistent with reduced release into blood of form I relative to form II rABP rather than increased clearance of form I in adult animals.

Androgen binding protein (ABP), produced by Sertoli cells and released into seminiferous tubules and blood, was measured in the serum of di-n-pentyl phthalate (DPP)-treated rats as a potential index of germinal epithelial damage. A single oral dose of DPP (0, 0.25, 1.0, or 2.0 g/kg body wt in corn oil) was given to four groups of 110 Fischer 344 rats; 10 rats per group were killed weekly for 10 weeks. Effects of treatment on serum ABP were then compared with effects on other reproductive endpoints. Treatment did not produce any significant effect on body weight or weights of liver, kidney, prostate, and seminal vesicles. In high-dose rats, serum ABP values more than doubled 2 days after injection, remained significantly elevated for 3 weeks, then fell and remained significantly below control values from Week 4 through Week 10. Accordingly, 95% of the rats in this group showed greater than 50% of the seminiferous tubules degenerated, decreased epididymal sperm density, reduced testicular and epididymal weights, and up to 97% morphologically abnormal sperm. In medium-dose rats, serum ABP increased up to 48% during the first week, returned to control values by Week 2, and remained at control levels thereafter. Of these rats, 20% showed 20-50% degenerated tubules, decreased sperm density, reduced testicular and epididymal weights (which were not always statistically significant), and up to 23% abnormal sperm morphology. In low-dose rats, serum ABP levels were similar to those of controls, and the other parameters, except sperm density, also remained unchanged. To examine the effects of DPP on fertility, a second group of rats was exposed in an identical manner [gavaged once with DPP in corn oil (0, 0.25, 1.0, and 2.0 g/kg body wt)], then mated to untreated females at 3, 6, and 10 weeks postexposure. DPP at 2 (but not 1.0 or 0.25) g/kg caused a significant reduction in pregnancies and live pups and a significant increase in preimplantation loss. Histopathology of the testis in the first experiment suggested a very slow recovery. Therefore, controls and high-dose rats in the mating trial were killed 14, 18, and 30 weeks after dosing and the germinal epithelium was evaluated histologically. All high-dose animals showed testicular lesions typical of phthalate ester exposure and the epithelium did not recover within 30 weeks.(ABSTRACT TRUNCATED AT 400 WORDS)

Dose-related effects of radiation upon the seminiferous epithelium were examined in the prepubertal rat. Marked damage to the spermatogenic cell populations was produced by doses of 5 Gy and above. As a result serum levels of FSH were increased, maximum changes being observed at 2 weeks, but levels remaining high even at 36 weeks after irradiation. Serum levels of androgen binding protein (ABP) were inversely related to serum FSH. Above a threshold dose of 5 Gy, serum ABP levels were reduced to between 30-50% of control values, possibly indicating damage to the Sertoli cells. Progression in the degree of testicular failure was indicated at 36 weeks after a dose of 15 Gy by further increases in serum gonadotrophins when compared to earlier times and by the absence of spermatogenesis.

The microheterogeneity of androgen-binding protein (ABP) from rat serum and epididymis was examined by subjecting purified native or deglycosylated preparations to analysis by one- or two-dimensional polyacrylamide gel electrophoresis (PAGE) followed by electrophoretic transfer to nitrocellulose and immunochemical localization. Analysis of native ABP by one-dimensional sodium dodecyl sulfate-PAGE confirmed earlier observations that it is composed of subunits and that the subunits of serum ABP had higher apparent molecular weights than those of epididymal ABP. Treatment with neuraminidase, N-glycanase, or O-glycanase, alone or in combination, resulted in decreases in the apparent molecular weight of the subunits. These analyses indicated that terminal sialic acid residues and Asn-linked oligosaccharides were present on both subunits of ABP from the two sources. The fact that the greatest reduction in the Mr of the heavy subunit occurred following treatment with all three enzymes provides evidence that O-linked sugars are present on it. While enzyme treatment did not result in the appearance of a single subunit, chemical deglycosylation did (Mr 39,600). The carbohydrate composition of the heavy and light subunits of intact serum and epididymal ABP was 22 and 9% and 19 and 8%, respectively. Analysis by two-dimensional PAGE indicated that both subunits of the ABPs were composed of isoelectric variants. Although ABP from the two sources had several variants in common, differences were also observed. Treatment of the ABPs with the enzymes resulted in a shift of the pI values to a more basic pH range, indicating that carbohydrate removal also removed charged moieties. The most dramatic shift in the pI values of the isoforms occurred when O-glycanase was present in the enzyme mixture, providing further evidence for the presence of O-linked oligosaccharides on ABP. Isoelectric variants were present even after chemical deglycosylation of ABP.

Androgen-binding protein (ABP) was measured in serum and testicular interstitial fluid (IF) from rats during sexual maturation or in adult rats in which impairment of spermatogenesis had been induced by (i) testosterone withdrawal following Leydig cell destruction, (ii) local heating (43 degrees C) of the testes for 30 min or (iii) induction of unilateral cryptorchidism (UCD). The changes observed were related to the IF levels of testosterone and, in most instances, to the serum levels of FSH. The levels of ABP in serum and IF decreased together with age, being highest at 30 days, falling steeply by 40 days and then slowly but progressively up to 100 days of age. A similar pattern was observed for serum FSH, except that the initial fall occurred beyond 40 days of age. Treatment with EDS or exposure to local heating caused comparable reductions in testicular weight (25-30% by 7 days after treatment, 50% by 21-28 days) and raised the serum levels of FSH. In both groups the levels of ABP in IF were increased by two- to three-fold while the levels of testosterone were either reduced markedly (EDS-treatment) or remained unchanged (local heating). In rats made UCD for 60 days, the weight of the abdominal testis was reduced by 75%, compared with the contralateral scrotal testis, while the IF levels of ABP and testosterone were significantly increased (55%) and decreased (90%), respectively. Short-term (3 days) deprivation of testosterone in adult rats, following immunoneutralization of LH, was without significant effect on IF levels of ABP. It is concluded that ABP secretion into IF is increased in situations of subnormal (or sub-adult) numbers of germ cells and this is usually associated with high levels of FSH. Measurement of ABP levels in IF should prove of value for the monitoring of Sertoli cell function in vivo and may be of diagnostic use for the detection of changes in germ cell numbers.

We further studied the androgen-binding protein (ABP) that we recently evidenced in the serum from two patients with hydatidiform mole [Ref. 4]. This protein was further shown to be distinct from the sex hormone-binding globulin (SHBG) by concanavalin A and ion-exchange chromatographies, as well as spectrophotometric and kinetic studies. However, the ABP was shown to have a molecular weight and relative affinities for several steroids, similar to those of SHBG. Our results lead us to suppose that the ABP previously evidenced in molar vesicles and fluid [Ref. 5] is secreted in the serum. It is, however, likely that the secretion process alters the binding affinity of this protein. The presence of this additional binding component in the serum of patients with such trophoblastic tumours, may reduce severely the free 17 beta-hydroxyandrogens levels, as well as may help create a release gradient in the serum steroids buffer stores.

The indazole carboxylic acid derivative, tolnidamine, has marked antispermatogenic activity in several animal species. In this study, we assessed the effect of tolnidamine on rat Sertoli cell function both in vivo and in vitro, using androgen binding protein (rABP) as a marker. Groups of six male rats were killed 2, 4, 8, 16, 32, 64 hours and 5, 8, and 12 days following tolnidamine administration (250 mg/kg by oral gavage). There was a progressive reduction in both testicular and epididymal weights. Serum FSH levels did not change and LH showed a transient increase between 64 hours and 8 days. Except for an initial increase at 2 hours, there were no changes in serum testosterone. Epididymal rABP concentration and content declined as early as 8 hours, with the lowest values occurring at 5 and 12 days. By 16 hours, there was an increase in testicular rABP, which was also evident at 8 days and 12 days. Within 16 hours after tolnidamine, there was a rise in serum rABP, which persisted until the end of the experiment. When another indazole carboxylic acid derivative, lonidamine, was administered (250 mg/kg), similar changes were evident in epididymal and serum rABP at 32 hours, but the rapid decrease in testicular rABP suggested a different mechanism of action. In another experiment, single oral doses of tolnidamine (50, 100, 250, and 500 mg/kg) were administered to other groups of rats and the animals were killed after 24 hours and 5 days. With increasing doses of tolnidamine, there was a reduction in epididymal rABP concomitant with an increase in testis and serum rABP levels.(ABSTRACT TRUNCATED AT 250 WORDS)

The interaction of 3H-5 alpha-dihydrotestosterone, 3H-progesterone, 3H-cortisol and 3H-testosterone with the Cyprinus carpio blood proteins was studied by means of adsorption on the activated charcoal and equilibrium dialysis. Protein which specifically binds androgen-, estradiol-, progesterone- and, to a lesser degree, corticosteroids was present in the blood plasma. The equilibrium constants of 3H-steroid association with this protein, the concentration off steroid-binding sites and its hormonal specificity of the affinity were determined. There were no pronounced sex dimorphism and marked alterations in the concentration of protein-binding sites during ontogeny and reproduction process. Protein, being specialized on the corticosteroid transport, was not revealed in the Cyprinus carpio blood plasma. It is suggested that the formation of differentiated corticosteroid-binding globulin and sex steroid-binding protein, typical of higher vertebrates, occurred during the stage of teleostei.