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Background Fibrous dysplasia is characterized by intense marrow fibrosis and increased rates of bone turnover. The lesions of fibrous dysplasia resemble those described in the long bones of transgenic mice overexpressing the c-fos proto-oncogene. Activating mutations in the alpha subunit of the stimulatory guanine-nucleotide-binding protein (GS alpha) linked to adenylate cyclase have recently been described in bone cells from patients with the McCune-Albright syndrome and fibrous dysplasia. Methods We used in situ hybridization to determine the level of expression of c-fos in bone-biopsy specimens from two normal subjects, eight patients with fibrous dysplasia, and six patients with other bone disorders characterized by high rates of bone turnover. The probe used corresponded to the fourth exon of the c-fos gene. Results High levels of c-fos expression were detected in the bone lesions from all eight patients with fibrous dysplasia. No expression of c-fos was detected in bone specimens from the normal subjects or from specimens of normal bone obtained from patients with fibrous dysplasia. The cells that expressed c-fos in the dysplastic lesions were fibroblastic and populated the marrow space. A very low level of c-fos expression was detected in the biopsy specimens from the patients with other bone diseases. One patient with polyostotic fibrous dysplasia and one patient with the McCune-Albright syndrome were tested for the previously described GS alpha gene mutations and were found to express these mutations in bone. Conclusions Increased expression of the c-fos proto-oncogene, presumably a consequence of increased adenylate cyclase activity, may be important in the pathogenesis of the bone lesions in patients with fibrous dysplasia.

DNA microarrays are a powerful technology that can provide a wealth of gene expression data for disease studies, drug development, and a wide scope of other investigations. Because of the large volume and inherent variability of DNA microarray data, many new statistical methods have been developed for evaluating the significance of the observed differences in gene expression. However, until now little attention has been given to the characterization of dispersion of DNA microarray data. Here we examine the expression data obtained from 682 Affymetrix GeneChips® with 22 different types and we demonstrate that the Gaussian (normal) frequency distribution is characteristic for the variability of gene expression values. However, typically 5 to 15% of the samples deviate from normality. Furthermore, it is shown that the frequency distributions of the difference of expression in subsets of ordered, consecutive pairs of genes (consecutive samples) in pair-wise comparisons of replicate experiments are also normal. We describe a consecutive sampling method, which is employed to calculate the characteristic function approximating standard deviation and show that the standard deviation derived from the consecutive samples is equivalent to the standard deviation obtained from individual genes. Finally, we determine the boundaries of probability intervals and demonstrate that the coefficients defining the intervals are independent of sample characteristics, variability of data, laboratory conditions and type of chips. These coefficients are very closely correlated with Student's t- distribution. In this study we ascertained that the non-systematic variations possess Gaussian distribution, determined the probability intervals and demonstrated that the K α coefficients defining these intervals are invariant; these coefficients offer a convenient universal measure of dispersion of data. The fact that the K α distributions are so close to t- distribution and independent of conditions and type of arrays suggests that the quantitative data provided by Affymetrix technology give "true" representation of physical processes, involved in measurement of RNA abundance. This article was reviewed by Yoav Gilad (nominated by Doron Lancet), Sach Mukherjee (nominated by Sandrine Dudoit) and Amir Niknejad and Shmuel Friedland (nominated by Neil Smalheiser).

Chronic treatment of adult men with LHRH agonists causes a decrease in serum testosterone and 5 alpha-dihydrotestosterone to castrate levels. In the presence of such low levels of circulating testicular androgens, the concentration of serum LH measured by radioimmunoassay (RIA) sometimes remains normal or is only partially inhibited. In order to assess the biological activity of circulating LH, we have used the mouse interstitial cell assay. Blood samples were obtained from patients with prostatic carcinoma treated with the LHRH agonist [D-Trp6] LHRH ethylamide in combination with the pure antiandrogen Flutamide (Euflex). While serum LH levels measured by RIA were only partially reduced from 2.2 +/- 0.3 (SEM) to 1.1 +/- 0.1 ng/ml after 3 months of therapy, bioactive LH was markedly inhibited from 0.43 +/- 0.04 to 0.030 +/- 0.007 ng/ml, thus causing the ratio of biologically active to radioimmunoassayable LH to drop from 0.26 +/- 0.03 to 0.03 +/- 0.01. In the same patients, serum testosterone levels were decreased from 3.91 +/- 0.51 to 0.14 +/- 0.05 ng/ml after 3 months of treatment. In patients treated for 6 months, the bio/immuno ratio was still reduced at 0.032 +/- 0.005. These data show a marked loss of LH biological activity during treatment of adult men with an LHRH agonist and an antiandrogen. The close parallelism observed between serum testosterone and bioactive LH levels suggests that the loss of biological activity of the gonadotrophin is mainly, if not exclusively, responsible for the inhibition of testicular androgen secretion observed during chronic treatment with LHRH agonists.

In order to further understand the factors which influence the normal or pathologic growth of the prostate, we have characterized the receptor for epidermal growth factor (EGF) in the rat ventral prostate and have studied the hormonal regulation in this receptor. EGF binds to a single class of saturable, high affinity binding sites in total prostatic homogenate. Scatchard analysis of the binding data reveals an apparent dissociation constant (Kd) of 0.93 ± 0.08 nM and a number of sites of 4.01 ± 0.24 fmol per mg protein. Among the peptides tested, only native EGF can displace bound [125I]EGF. Castration stimulates the concentration of prostatic EGF receptors from 25.5 ± 3.0 to 43.4 ± 5.4 fmol/100 mg tissue in intact and castrated animals, respectively (P < 0.01). Treatment of castrated rats with dihydrotestosterone (DHT) inhibits the rise in prostatic EGF receptor concentration induced by orchiectomy, while estradiol, progesterone or the dopaminergic agonist CB-154, have no effect. Combined administration of DHT with the other above-mentioned steroids or CB-154 does not modify the inhibition of prostatic EGF receptor concentration induced by the androgen in castrated animals. When the data are expressed as changes in EGF receptor number in the total prostate, DHT treatment reverses the inhibitory effect induced by castration and yields an EGF binding capacity comparable to that measured in intact animals. Chronic treatment with a pure antiandrogen or a potent LHRH agonist (LHRH-A) alone has no significant effect on EGF receptor concentration in prostatic tissue, although, secondary to a reduction in prostatic weight, total prostatic EGF binding capacity is reduced following antiandrogen or LHRH-A treatment. When the agonist, however, is administered in combination with the antiandrogen, the concentration of prostatic EGF receptors rises from 12.1 ± 1.3 fmol/100 mg tissue in intact animals to 35.8 ± 4.0 fmol/100 mg tissue in animals receiving the combined treatment with the highest (9 mg/day) dose of antiandrogen. This degree of stimulation (about 300%) is comparable to the stimulation induced by castration. While both prostatic EGF binding capacity and tissue weight are strongly modulated by androgens, the effect on EGF receptors is of smaller magnitude, thus indicating a relative stability of this parameter in the prostatic tissue. The presence of specific and high affinity receptors for EGF in the rat ventral prostate and the

Epidermal growth factor (EGF) is a Mr 6045 polypeptide first characterized for its ability to stimulate mitogenesis in epidermal and epithelial cells. The first step in the action of the growth factor is its binding to specific, high affinity membrane receptors. These receptors have been studied in a number of tissues and cell culture lines. The level of EGF receptors is modulated by many agents. EGF down-regulates its receptor. In addition, the number of EGF receptors is decreased by other growth factors (platelet-derived growth factor; transforming growth factor), by many tumor promoters and by viral transformation. Several hormones also can regulate EGF binding in its target tissues.

Daily subcutaneous administration of 50 μg of the luteinizing hormone-releasing hormone (LHRH) agonist [D-Trp 6 ]LHRH ethylamide in adult dogs causes a transient increase in the serum testosterone (T) concentration which reaches a maximum at 200% above control on days 2–4 of treatment and progressively decreases to 7% of the pretreatment value on day 21, the last time interval studied. After a transient increase, the concentration of serum bioactive luteinizing hormone (LH) was progressively decreased on days 11 and 19, thus suggesting that in analogy with human findings, the loss of LH bioactivity is responsible for the inhibition of testicular steroidogenesis induced in the dog by LHRH agonists. Of major significance is the finding that the changes in serum T levels observed during the first 3 weeks of treatment, as well as the complete inhibition of the intratesticular concentration of sex steroids observed at the end of this period of treatment with the LHRH agonist were not affected by simultaneous administration of flutamide (125 mg per os every 8 h). Such findings indicate that at the dose used, the LHRH agonist is in full control of gonadotropin secretion, thus completely overcoming feedback influences. Since the administration of the antiandrogen flutamide does not decrease the efficacy of the LHRH agonist as blocker of testicular androgen biosynthesis, the present data support the use of a pure antiandrogen in order to neutralize the effect of the transient rise in testicular androgen secretion which always accompanies the first days of treatment with LHRH agonists in patients with advanced prostate cancer.

It is now well established that chronic treatment with GnRH agonists offers an advantageous alternative to orchiectomy and estrogens for the treatment of prostate cancer. Castration levels of androgens can thus be easily achieved without side effects other than those related to castration levels of serum androgens. However, man is unique among species in having a high secretion rate of precursor adrenal steroids which are converted into active androgens in the normal prostate and prostatic cancer. All the enzymes required for the transformation of dehydroepiandrosterone sulfate, dehydroepiandrosterone, androstenedione, and androst-5-ene-3 beta, 17 beta-diol are present in prostatic tissue. Moreover, as shown in many systems, castration levels of serum testosterone (T) at 0.2-0.4 ng/ml exert significant androgenic activity in target tissues. In order to inhibit the action of androgens of both testicular and adrenal origin, GnRH agonists have been administered in association with the pure antiandrogen Flutamide in patients having clinical stage D2 (bone metastases) prostate cancer. A positive objective response assessed according to the criteria of the United States National Prostatic Cancer Project (USNPCP) has been observed in 84 of the 88 patients who had received no previous treatment (95.4%). After 2 yr of treatment, the probability of continuing response is 70% compared to 0-10% by previous approaches. In addition, the death rate at 2 yr is at 10.9% as compared to approximately 50% after standard hormonal therapy. When the same treatment was applied to patients who had received previous hormonal therapy (orchiectomy, estrogens or GnRH agonists alone) before showing a relapse, the response rate decreased to 62.9% and the death rate at 2 yr was 52%.(ABSTRACT TRUNCATED AT 250 WORDS)

Rat ovarian epidermal growth factor (EGF) receptors were characterized in total ovarian homogenate obtained from animals at random stages of the estrous cycle. A single class of specific and high-affinity binding sites with an apparent dissociation constant (KD) of 1.1 +/- 0.2 nM and a total site number of 78 +/- 4 fmoles/mg protein (652 +/- 17 fmoles/100 mg wet tissue) was observed. In 4-day cycling rats, ovarian EGF receptor levels are high (200 fmoles/100 mg ovary) on the morning of estrus as well as in the afternoon of proestrus and are lower by 30, 60 and 55% on the morning of diestrus I, diestrus II and proestrus, respectively. Chronic administration of an LHRH agonist is accompanied by low ovarian EGF receptor levels comparable to those observed on diestrus II. In intact or hypophysectomized female rats pretreated with pregnant mare's serum gonadotropins, administration of ovine follicle-stimulating hormone or human chorionic gonadotropin increases ovarian EGF receptor concentration and content while the administration of ovine prolactin, 17 beta-estradiol or progesterone has no effect. Treatment with dihydrotestosterone or testosterone slightly reduces ovarian EGF binding in intact but not hypophysectomized animals. The variation of ovarian EGF receptor levels observed during the estrous cycle as well as the modulation of these receptors by the administration of exogenous gonadotropins suggest that EGF could well play a physiological role in the regulation of ovarian functions.

The binding characteristics and specificities of the National Hormone and Pituitary Program (NHPP) kits for the radioimmunoassay of the alpha- and beta-subunits of human luteinizing hormone (hLH-alpha and hLH-beta) were studied, as well as the specificities of the anti-hLH and anti-human follicle stimulating hormone (anti-hFSH) antisera distributed by the same organization. The affinity constants of the anti-hLH-alpha and anti-hLH-beta antisera were calculated at 157 +/- 8.4 nM-1 and 109 +/- 7.4 nM-1, respectively. Both antisera were highly specific with regard to the other subunit. However, in the homologous hLH-alpha RIA, native hLH cross-reacted at 21.9%, hFSH at 17.5% and hTSH at 7.9%. The alpha-subunit of the human chorionic gonadotropin, hCG-alpha, was equipotent with the hLH-alpha standard in this assay. In the homologous hLH-beta RIA, hLH showed a cross-reactivity of 14.7% while the cross-reactivities of hCG-beta, hFSH and hTSH were 3.5%, 1.2% and 0.6%, respectively. The anti-hFSH antiserum was highly specific, while the anti-hLH antiserum showed non parallel competition curves. With this knowledge of the specificity of each antiserum, corrections can be properly made for the assays of hLH, hLH-alpha and hLH-beta while the hFSH RIA can be used without correction for the presence of the three other components.

Up to day 6 of treatment of adult dogs, daily subcutaneous administration of 50 micrograms of the LHRH agonist [D-Trp6, des-Gly-NH2-10]LHRH ethylamide causes up to a 3-fold increase in serum testosterone (T) concentration which is followed by a progressive decrease to castration levels (less than or equal to 0.2 ng/ml) at later time intervals (up to 21 days, the last time interval studied). Both aminoglutethimide and ketoconazole, two inhibitors of steroid biosynthesis, cause a 30-40% rise in serum T when administered alone. However, either drug administered in combination with the LHRH agonist completely blocks the transient rise in serum T observed when the LHRH agonist is administered alone. On the other hand, the LHRH agonist prevents the secondary rise in steroid secretion observed when either of the two inhibitors of steroid secretion is used alone. Administration of the pure antiandrogen Flutamide alone or in combination with LHRH-A and an inhibitor of steroid biosynthesis does not influence serum T levels. When the serum levels of pregnenolone, 17-OH-pregnenolone, progesterone, 17-OH-progesterone, dehydroepiandrosterone (DHEA), androstenedione (delta 4-dione), androst-5-ene-3 beta, 17 beta-diol (delta 5-diol), T, dihydrotestosterone (DHT), androstane-3 alpha, 17 beta-diol, androstane-3 beta. 17 beta-diol and 17 beta-estradiol (E2) are analyzed in detail, it can be seen that both aminoglutethimide and ketoconazole not only prevent the rise in serum steroids observed during the first 8 days of treatment with the LHRH agonist but that both compounds enhance the inhibitory effect of the LHRH agonist at later time intervals. A predominant inhibitory effect of ketoconazole is exerted on 17,20-desmolase activity. Aminoglutethimide has little influence on the loss of serum LH bioactivity induced by the LHRH agonist while ketoconazole stimulates the concentration of serum bioactive LH in the absence or presence of simultaneous treatment with the LHRH agonist. The present data clearly demonstrate that aminoglutethimide or ketoconazole can prevent the rise in serum androgens accompanying the first days of treatment with an LHRH agonist in the dog. Moreover, after 3 weeks of treatment, the inhibitory effect of the LHRH agonist on serum androgen levels is enhanced by addition of aminoglutethimide or ketoconazole. Moreover, Flutamide does not interfere with the inhibitory action of the LHRH agonist, aminoglutethimide or ketoconazole, thus suggesting that maximal inhibition of androgen action is likely to be achieved by a combination of these drugs.

Discovery of LHRH1,2 and the availability of its potent agonistic analogues has led to a rapid increase in our knowledge of the pituitary-gonadal axis and has offered new and exciting therapeutic approaches in reproductive endocrinology as well as in sex steroid-dependent diseases.

Stimulated by the unexplained lack of success of LHRH and its agonists in the treatment of infertility in men1, we investigated in detail the effect of acute and chronic administration of these peptides on testicular functions in experimental animals. We then made the observation that short-term administration of an LHRH agonist to adult male rats leads to a loss of testicular LH and prolactin receptors, as well as to decreased serum testosterone levels accompanied by inhibition of ventral prostate, seminal vesicle and testis weight2–5. It is of great interest that, among the species so far studied, man is the most sensitive to the inhibitory effect of treatment with LHRH agonists on testicular steroidogenesis5,6. In fact, while, in the rat, treatment with LHRH agonists increases 5α-reductase activity and formation of 3α-androstanediol as well as 5α-dihydrotestosterone, which can partially counteract the inhibitory effect on testosterone production5,7, no such effect is seen in man, where androgen biosynthesis can be completely inhibited and medical castration is thus achieved relatively easily with no secondary effect other than those related to low circulating androgen levels5,8,9.

The importance of prolactin (PRL) in the development and growth of the mammary gland and experimental mammary tumors is clearly established. Prolactin, however, does not act alone in its stimulatory action on normal mammary development nor in its role as an initiator or co-inducer of mammary tumors. A number of other hormones such as estrogens, progesterone, glucocorticoids, thyroid hormones, insulin and growth hormone have been shown to be important for full development and action of the mammary gland (21) and are undoubtedly of great importance in the evolution and maintenance of mammary tumors.

Cancer of the prostate is the second cause of death due to cancer in man, its annual incidence being approximately 40,000 new cases per 100 millions of population in North America. A major change in the treatment of this disease has been introduced by the pioneering studies of Huggins and collaborators who have recognized the role of androgens of testicular origin in the evolution of this cancer (Huggins and Hodges, 1941; Huggins et al., 1941). Following these observations, during the last forty years, neutralization of testicular androgens has been achieved by surgical castration or treatment with estrogens, two approaches which lead to subjective and/or objective improvement in 60 to 70% of cases for various time intervals (Bailar et al., 1970; Barnes and Ninan, 1972; Byar, 1973; Grayhack and Kozlowski, 1980; Murphy and Slack, 1980; Nesbit and Plumb, 1946; Nesbit and Baum, 1950; Staubiz et al., 1954; Whitmore, 1956). However, surgical castration presents psychological limitations for many patients while high doses of estrogens frequently cause lethal cardiovascular complications (Byar, 1973). There was thus the need for a more acceptable way of neutralizing testicular androgens.