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Beer is one of the most popular alcoholic beverages consumed by young people. Ethanol intake is associated with harmful effects to the reproductive system. Bioactive compounds present in beer may diminish the toxics effect of ethanol. However, there is still little knowledge about the effect of beer consumption on hormonal regulation of male reproduction in organisms exposed to alcohol after the peripubertal age. Therefore, the aim of this study was to determine the influence of beer intake on plasma reproductive hormones, immunolocalization of cleaved caspase-3 (casp-3), and the level of the neuronal isoform of nitric oxide synthase (nNOS) in Leydig cells (LCs) in adolescent male Wistar rats. The animals, beginning at the age of 30 days, drank beer (10% ethanol; B2 group [2 weeks' exposure] and B4 group [4 weeks' exposure]), 10% ethanol solution (CE2 group [2 weeks' exposure] and CE4 group [4 weeks' exposure]), or water (C2 group [2 weeks' exposure] and C4 group [4 weeks' exposure]). Rats drinking beer for 4 weeks showed higher phenolic acid intake compared to rats drinking beer for 2 weeks. Rats exposed to beer for 4 weeks showed decreased plasma levels of follicle-stimulating hormone (FSH) and 17β-estradiol (E2) (3.173 ng/mL and 11.49 pg/mL, respectively), compared to the CE4 (5.293 ng/mL and 43.912 pg/mL, respectively) and the C4 groups (5.002 ng/mL and 41.121 pg mL, respectively). Expression of cleaved caspase-3 in LCs was lower in the B4 group rats, compared to the CE4 group rats (ID score: 1.676 vs. 2.190). No changes in nNOS expression were observed. Beer consumption revealed a similar negative effect on hormonal regulation of male reproductive function, but lower apoptosis in LCs may be beneficial for steroidogenic activity., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Introduction Alzheimer's disease (AD) is a progressive and irreversible neurodegenerative disease. Typical features of AD include memory loss, social dysfunction and physical impairment. Although the pathological findings in the central nervous system are well established, the etiological factors are poorly known. Recent studies suggested the role of metabolic disturbances in the development of AD neurodegeneration. Adiponectin, an anti-inflammatory and metabolism regulating factor, was linked to AD. Aim The aim was to examine whether adiponectin fractions combined with insulin/insulin resistance-associated metabolic parameters correlate with AD progression. Material and methods The study comprised 98 women: 27 with moderate to severe AD, 31 with AD at early stage and 40 healthy controls, matched for age and BMI. To evaluate memory impairment, the MMSE was performed. Plasma total adiponectin and its high-, medium- and low molecular weights were measured with ELISA. Anthropometric, clinical and metabolic parameters were assessed. Correlations between adiponectin array and measured parameters were evaluated. Results In comparison to the controls, enhanced levels of total and medium molecular weight adiponectin characterized AD individuals. In AD, we found correlations between adiponectin array, and anthropometric and biochemical parameters. After adjustment to BMI, a significant increase of the total adiponectin and high- and medium molecular weight fractions was observed. A negative correlation between low molecular weight adiponectin and MMSE was found. Conclusions Our results indicate a possible link between adiponectin variations and AD. We hypothesize that changes in adiponectin profile observed in AD result from compensatory mechanism against neuropathological processes, as well as from adiponectin homeostasis impairment.

Background: Multiple sclerosis (MS) is a demyelinating autoimmune disease of the central nervous system with possible involvement of vascular dysregulation secondary to endothelial dysfunction caused by destruction of the vessel wall. Vascular dysregulation leads to excessive vasoconstriction or insufficient vasodilatation, resulting in vasospasm mediated by endothelin-1 (ET-1), the most potent and long-lasting mediator. Vascular dysregulation can play an important role in the pathogenesis of some eye disorders and it has been hypothesized that it is a vascular risk factor for glaucomatous optic neuropathy. The aim of this study was to estimate endothelin-1 (ET-1) plasma levels in patients with MS., Material and Methods: The MS group consisted of 39 patients (9 males, 30 females), mean age: 38.8 ± 10.02 years, range: 22-62. The control group consisted of 27 healthy volunteers (3 males and 24 females), mean age: 37.4 ± 10.88 years, range: 20-62; clinically, in a non-active stage of the disease. ET-1 plasma levels were measured using the Endothelin-1 ELISA Kit (Immuno-Biological Laboratories Co., Japan). Statistical analysis was performed with the nonparametric Mann-Whitney U test for independent groups., Results: Endothelin-1 (ET-1) plasma levels were significantly lower in MS patients compared to healthy controls: mean value 0.55 ± 0.44 pg/ml (146.05 ± 118.27 fmol/ml) vs. 0.95 ± 0.48 pg/ml (252.83 ± 127.16 fmol/ml); P=0.012., Conclusions: Significantly decreased ET-1 plasma levels in the MS patients could reflect the non-active disease at the time of ET-1 measurements or the effects of immunomodulatory treatment, but it cannot be excluded that decreased ET-1 plasma levels in these patients might result from vascular dysregulation.

EGR1 and PITX1 are transcription factors required for gonadotroph cell Lhb promoter activation. To determine changes in Egr1 and Pitx1 mRNA levels in central and peripheral pituitary stimulations, an in vivo model based on i.c.v. pulsatile (1 pulse/0.5 h over 2 h) GnRH agonist (1.5 nM buserelin) or antagonist (2 nM antide) microinjections was used. The microinjections were given to ovariectomised and 17β-oestradiol (E2) (3×20 μg), ERA (ESR1) agonist propyl pyrazole triol (PPT) (3×0.5 mg), ERB (ESR2) agonist diarylpropionitrile (DPN) (3×0.5 mg) s.c. pre-treated rats 30 min after last pulse anterior pituitaries were excised. Relative mRNA expression was determined by quantitative RT-PCR (qRT-PCR). Results revealed a gene-specific response for GnRH and/or oestrogenic stimulations in vivo. Buserelin pulses enhanced Egr1 expression by 66% in ovariectomised rats, whereas the oestradiol-supplemented+i.c.v. NaCl-microinjected group showed a 50% increase in Egr1 mRNA expression. The oestrogenic signal was transmitted via ERA (ESR1) and ERB (ESR2) activation as administration of PPT and DPN resulted in 97 and 62%, respectively, elevation in Egr1 mRNA expression. A synergistic action of GnRH agonist and 17β-oestradiol (E2) stimulation of the Egr1 gene transcription in vivo were found. GnRHR activity did not affect Pitx1 mRNA expression; regardless of NaCl, buserelin or antide i.c.v. pulses, s.c. oestrogenic supplementation (with E2, PPT or DPN) consistently decreased (by -46, -48 and -41% respectively) the Pitx1 mRNA in the anterior pituitary gland. Orchestrated Egr1 and Pitx1 activities depending on specific central and peripheral regulatory inputs could be responsible for physiologically variable Lhb gene promoter activation in vivo., (© 2014 Society for Endocrinology.)

Very little is known about the effects of red wine consumption on male reproductive functions. Here we report the effect of regular drinking of different types of red wine on hormonal reproductive parameters and total antioxidant status in young adult male rats. Dry red wine (D-RW) exerted higher antioxidant activity and was characterized by higher concentration of phenolic compounds compared to semi-dry (SD-RW), sweet (S-RW) and semi-sweet (SS-RW) wines. No differences in total antioxidant status of rat plasma after six weeks of drinking of the wines were detected. Increased plasma follicle-stimulating hormone levels in S-RW versus control and D-RW (5.26 vs. 3.06 and 3.21 ng mL(-1)) groups were found. The plasma testosterone concentration was lower in D-RW compared to control, SD-RW, S-RW and SS-RW groups (0.25 vs. 1.12, 1.09, 1.54 and 1.25 ng mL(-1)). Higher plasma 17β-estradiol level in S-RW versus SD-RW and SS-RW (10.94 vs. 7.18 and 6.72 pg mL(-1)) group was stated. The prolactin level was higher in plasma of S-RW versus D-RW and SS-RW (17.35 vs. 9.74 and 8.59 ng mL(-1)) rats. The effects of red wine drinking on the hormonal regulation of the male reproductive system depend on the type and the dose of red wine. Chemical compounds naturally occurring in red wines (i.e. phenolics) may modulate the effects of ethyl alcohol, but also directly affect the male reproduction.

Objectives: Orexin A (OxA) is a regulatory neuropeptide which is involved in the control of various autonomic and neuroendocrine functions. It regulates sleep-wake cycle, food intake and modulates the hypothalamic and pituitary hormones secretion. Orexin A acts through two types of receptors, which proved to exist in the pituitary. This may indicate the possibility of direct action of OxA on the adenohypophysis level. The aim of this study was to evaluate the direct effect of orexin A on gonadotropin (LH and FSH) release from cultured pituitary cells of immature female rats as well as mature female rats (ovariectomized and ovariectomized and estradiol treated rats)., Material and Methods: The effect of 0.1 nM and 100 nM orexin A on LH and FSH release from anterior pituitary cells after 1 h of incubation was examined in immature female rats (IM) as well as mature female (ovariectomized - M/OVX; and ovariectomized and estradiol treated - M/OVX+E2) rats. The concentration of LH and FSH in medium was determined by RIA method., Results: Orexin A at a dose of 0.1 nM and 100 nM significantly stimulated LH secretion in IM group. In M/OVX group release of LH was inhibited by OxA only in higher dose (100 nM). No effect of orexin A on FSH secretion was found., Conclusions: OxA may directly modulate LH secretion from cultured pituitary cells and it has the contradictory effect on LH release in immature and ovariectomized mature female rats.

Objective: It has been found that hGH-RH analogues with increased resistance to enzymatic degradation have a much higher potency than the native hGH-RH (1-29)-NH2 and have an ability to partially reverse growth hormone deficiencies., The Aim: The aim of these studies was to elaborate a method which can be used for preliminary evaluation of new GH-RH analogues both from the point of view of their potency to release GH and enzymatic stability., Method: Two highly active GH-RH analogues with increased resistance to trypsin-like enzymes, and hGH-RH(1-29)-NH2 used as a standard, in doses 1 nM, 10 nM, and 100 nM were added to pituitary rat cell culture, and medium was collected after 30, 60, 120 and 240 min. GH concentration was measured by RIA kit., Results: It was observed that the potency of these two GH-RH analogues was several times higher than that of native compound. Moreover, the stimulation was much longer. This suggests that high activity of these analogues in vivo could be the result of increased enzymatic stability., Conclusion: This method can be used for selecting more potent and more stable releasing peptides before in vivo evaluation.

Orexin A (OxA), a recently discovered neuropeptide, is synthesized mainly by neurons located in the posterolateral hypothalamus and is a 33 amino acid peptide with N-terminal pyroglutamyl residue and two inter-chain disulfide bonds. It is a potent agonist for both the orexin-1 (OxR1) and orexin-2 (OxR2) receptors. Orexin A and its receptors are widely distributed in the central nervous system (CNS) and peripheral organs suggesting the pleiotropic functions of this peptide. Orexin A is involved in food intake and energy expenditure in many species, but also plays an important role in the regulation of the hypothalamo-pituitary axes. The role of orexin A in the regulation of the hypothalamo-pituitary-adrenal, -thyroid, -somatotropic, and -gonadal axes has been inadequately investigated. Orexinergic fibres project to the septal-preoptic and arcuate nucleus-median eminence regions--two areas of the brain directly involved in the synthesis and release of gonadotropin-releasing hormone (GnRH). Contentious opinions concerning the influence of orexin A over the hypothalamo-gonadotropic axis have been reported in both in vivo and in vitro studies. Further studies are necessary to clarify relationships between orexin A and the hypothalamo-pituitary hormones involved in reproduction.

Objective: Amylin is a 37-amino acid peptide that is secreted from the pancreatic beta cells. This peptide is cosecreted with insulin from the pancreas by glucose. Amylin plays a role in glucose homeostasis and in the regulation of lipid metabolism. Amylin receptors were identified in central nervous system of rats. There is no available data on the effects of amylin on the pituitary hormones secretion. The aim of this study was to evaluate the effect of amylin on prolactin release in vivo and in vitro experiments in male adult Wistar Kyoto rats., Methods: Amylin in a dose of 1 microg/5 microl was injected intraventricularly (i.c.v) during 5 min. using automatic pump. The control group received 5 microl cerebrospinal fluid. Amylin was injected intravenously (i.v) in a dose of 10 microg in 300 microl 0.9% NaCl. The control group received 300 microl 0.9% NaCl. In vitro experiment was performed in the pituitary cells culture conditions. Amylin was added to pituitary cell culture in a dose of 1, 10, 100 nM. Prolactin concentrations were determined using RIA methods., Results: Central or peripheral administration of amylin caused a significant decrease of serum PRL concentrations as compared with control after 120 min. After 240 minute incubation of the pituitary cells culture with amylin in doses of 10 nM and 100 nM a significant inhibition of the release of PRL was found. However we found that the effect of amylin on the release of PRL depended on dose and time of incubation. A significant increase of PRL level was observed in cultured media in the presence of 1 nM of amylin after 60 min., Conclusion: Our results indicate that amylin administrated centrally and peripherally as well in the cell culture inhibits PRL release.

Objective: Some neuropeptides and monoaminergic neurotransmitters may affect hypothalamic feeding centres, sympathetic activity and thermogenesis. Sibutramine (BTS54524; N-[1-[1(4-chloro phenyl) cyclobutyl]-3methyl N,N-dimethylamine hydrochloride monohydrate) is a new 5-HT serotonin and noradrenaline reuptake inhibitor (SNRI), antiobesity drug. The aim of this study was to evaluate the effects of the sibutramine therapy on plasma neuropeptide Y (NPY), insulin, leptin and beta-endorphin concentrations in obese patients., Methods: Sibutramine, serotonin and noradrenaline reuptake antiobesity drug was administered for 6 months in a dose of 10 mg daily in 60 obese women (BMI 30-40 kg/m2) (mean 34 kg/m2). Plasma NPY, leptin, beta-endorphin and insulin concentrations were measured with RIA methods using commercial kits (Peninsula Lab, Linco, Peninsula Lab, Swierk respectively). The above neuropeptides levels were evaluated before and after the 6 month sibutramine therapy in 60 obese women as well as in 30 obese women on low caloric diet and in 30 of the control group., Results: In 85% obese patients a decrease of body weight was found after 6 month therapy with sibutramine. A decrease in total cholesterol, LDL and triglycerides and an increase in HDL were observed after the sibutramine treatment. We have demonstrated that the sibutramine therapy leads to the decrease of plasma NPY, beta-endorphin, insulin and leptin concentrations in obese patients. After low diet therapy we have observed a decrease in plasma leptin levels, however we did not find significant changes in plasma leptin, NPY, beta-endorphin and insulin concentrations., Conclusions: We suggest that the effects on the disturbed activity of NPY, beta-endorphin, insulin and leptin may be involved in the mechanism of sibutramine action.

The direct monosynaptic pathway which exists between vasoactive intestinal peptide (VIP) and GnRH neurons in the hypothalamic preoptic area provides a neuroanatomical background for the modulatory effects of VIP exerted on GnRH neurons activity. Though central microinjection of VIP revealed its involvement in the modulation of LH release pattern, there is a lack of data concerning a possible VIP influence on the alpha and LHbeta subunit gene expression in the pituitary gland. Using a model based on intracerebroventricular pulsatile peptide(s) microinjections (1 pulse/h [10 microl/5 min] over 5 h) the effect of exogenous VIP (5 nM dose) microinjection on subunits mRNA content in ovariectomized/oestrogen-pretreated rats was studied. Subsequently, to obtain data concerning the involvement of GnRH and VIP receptor(s) in the regulation of alpha and LHbeta subunit mRNA expression, OVX/estrogen-primed rats received a pulsatile microinjections of 5 nM VIP with 3 nM antide (GnRH receptor antagonist) or 5 nM VIP with 15 nM VIP 6-28 (VIP receptor antagonist). In this case, substances were given separately with a 30 min lag according to which each antagonist pulse preceded a VIP pulse. Northern-blot analysis revealed that VIP microinjection resulted in a decreased alpha and LHbeta mRNA content in pituitary gland and this effect was dependent on GnRH receptor activity. Moreover, obtained results indicated that centrally administered VIP might operate through its own receptor(s) because a receptor antagonist, VIP 6-28, blocked the inhibitory effect of VIP exerted on both LH subunit mRNA content and LH release.

Objective: It has been reported that leptin plays an important role in the regulation of food intake and energy expenditure. There are controversial opinions about effects of leptin on the hormonal system. The aim of this study was to estimate the effect of leptin on pituitary hormones release after central and peripheral administration., Methods: Leptin was injected intracerebroventricularly (icv) in a dose of 0.5 microg/5microl aCSF (artificial cerebrospinal fluid) for 5 min in Wistar Kyoto rats. At 60 and 120 min after injections the animals were decapitated. Leptin in a dose of 10 microg in 300 microl of saline was administered intravenously (i.v). At 60 mins the animals were decapitated. Serum rLH, rFSH, rPRL, rTSH, rGH concentrations were measured with RIA methods., Results: After central (icv) injection of leptin we observed an increase of rGH, rTSH and a decrease of rPRL. However, after peripheral (iv) injection of leptin we found a decrease of rGH and rTSH and an increase of rPRL. We did not find any significant changes in LH and FSH after icv and iv injection of leptin., Conclusions: The opposite effects of leptin on pituitary hormones release were observed due to the method of leptin administration. Leptin may play a modulating role in the mechanism of pituitary hormones release.

Objectives: Galanin and its receptors are widely distributed within the central and peripheral nervous system, especially in hypothalamus including preoptic area, paraventricular nucleus (PVN), supraoptic nucleus (SON) and median eminence. Galanin plays an important role in the control of food intake, energy expenditure, reproduction, water balance and various neuroendocrine functions. Galanin may affect hormones release, but the exact mechanism of the peptide action remains unclear and possible direct effects of galanin on the pituitary are controversial. The aim of this study was to examine the effects of galanin on pituitary hormones release after the central and peripheral administration of the peptide., Material and Methods: (i) Experiment I - Intracerebroventricular (icv) administration of galanin: Galanin at a concentration of 0.5 microg in 5microl vehicle (artificial cerebrospinal fluid) or equal volume of the vehicle was slowly (1microl/min) infused into the third ventricle with an automatic pump (CMA/100; Sweden) through an inner cannula inserted into the guide cannula. After the end of the infusion the rats were transferred to their home cages with free access to food and water. At 60 min after the infusion of galanin or vehicle, animals were decapitated and trunk blood was collected in plastic tubes containing 1000 IU aprotinin (inhibitor of protease) per each ml of blood. (ii) Experiment II - Intravenous (iv) injection of galanin: Galanin in a dose of 10 microg in 300 microl of saline or 300 microl of saline alone was injected into the tail vein. After the injection the animals were transferred to individual cages with free access to food and water. At 60 min after the injection of galanin or saline, animals were decapitated, and trunk blood was collected in plastic tubes containing 1000 IU of aprotinin (Trascolan). The blood samples were centrifuged (3000 rpm for 20 min at 4 degrees C). Serum samples were frozen until hormonal analyses were performed. Serum rLH, rFSH, rPRL, rGH, rTSH concentrations were measured with RIA methods., Results: Galanin administered icv increased significantly rPRL and rTSH levels (p<0.01, p<0.05, respectively). Plasma rPRL and rTSH concentrations were not changed after iv injection of galanin. Galanin injected centrally inhibited significantly rGH release (p<0.01), however, galanin given iv stimulated rGH (p<0.01). Serum rLH and rFSH concentrations were not changed after icv and iv injections of galanin., Conclusion: Galanin may be involved in the modulating mechanism of pituitary hormones release.

Objectives: Functional studies indicate that bombesin may be involved in many physiological functions, including sensory transmission, the regulation of central autonomic pathways, thermoregulation, secretion of pituitary hormones, gastric and pancreatic secretion, food intake and satiety., Material and Methods: In order to evaluate the role of bombesin in the mechanism of pituitary hormones release the effects of bombesin on rGH, rTSH, rPRL, rFSH and rLH release were investigated in female Wistar-Kyoto rats. In studies 'in vitro' bombesin in a dose of 1nM, 10nM, 100nM was administered to pituitary cell culture. After 60, 120, 240 min. of incubation pituitary hormones were measured. In studies 'in vivo' bombesin was injected intraventricularly (icv) in a dose of 0.5 microg/5 microl aCSF (artificial cerebrospinal fluid) for 5 min. (experiment I). In experiment II bombesin was administered intravenously (iv) in a dose of 10 microg. After 60 min, 120 mins the animals were decapitated and serum rGH, rPRL, rTSH, rLH, rFSH concentrations were measured with RIA methods., Results: Bombesin stimulated rLH, rPRL, rTSH release from cultured pituitary cells. A slight increase of GH was also observed. After intravenous (iv) injection of bombesin an increase in serum rPRL and rGH levels was found. However, the intraventricular (icv) administration of bombesin leads to decrease of serum rGH, rPRL and rTSH concentrations., Conclusion: Our studies 'in vitro' and 'in vivo' indicate that bombesin may be involved in the modulation of pituitary hormones release.

Objective: It has been reported that the peptides such as orexins, neuropeptide Y (NPY) and leptin may play an important role in the regulation of appetite and energy metabolism. The interaction between leptin, orexins and NPY, as well as between peptides and insulin and cortisol in the different nutritional states have been investigated in animals. However, at present this relationship is poorly understood in humans., Research Methods: Material consisted of 36 obese women and 16 lean women. Plasma orexin A, orexin B, neuropeptide Y (NPY), leptin, insulin concentrations were measured with RIA methods., Results: Plasma orexin A concentrations were significantly lower in obese women as compared with control group. Plasma orexin A was significantly lower in severe obesity (BMI > 40 kg/m2) than that in moderate obesity (BMI < 40 kg/m2). Plasma orexin B concentrations did not change. However, plasma NPY, leptin and insulin levels were markedly higher in obese women, especially in severe obesity., Conclusions: Our results confirmed the thesis that orexin A, NPY, leptin play an important role in the regulation of energy metabolism in humans. In obesity the activity of these peptides is disturbed.

The aim of the study was to determine, using the rat model, whether uterine infections cause an increase in cytokine concentrations in peripheral blood, and whether this increase is accompanied by changes in the pituitary-ovarian axis function. The levels of tumor necrosis factor-alpha, interleukin-1beta, luteinizing hormone, follicle-stimulating hormone, prolactin, progesterone, testosterone and estradiol-17beta in blood plasma as well as the weight of the uterus were determined after intrauterine infusion of lipopolysaccharide (15 microg), peptidoglycan (1 mg) and Escherichia coli (10(6) cfu) suspension on the day of metaestrus. On days 3, 7 and 10 after treatment the rats were sacrificed to collect the blood samples. Inflammation of uterus and vaginal discharge developed in all rats after treatment. The administration of lipopolysaccharide, peptidoglycan and Escherichia coli induced considerable changes in ovarian cyclic activity, mainly diestrus was observed. Application of all these factors resulted in an increase (P<0.05, P<0.01) of plasma levels of tumor necrosis factor-alpha, interleukin-1beta, mainly on day 3 and 7. In the rats receiving pathological factors, the plasma levels of luteinizing hormone, follicle-stimulating hormone, prolactin and estradiol-17beta decreased (P<0.05, P<0.01) whereas progesterone and testosterone increased (P<0.05). These results indicate that in rats, the developing inflammatory process of the uterus following lipopolysaccharide, peptidoglycan and Escherichia coli infusions is connected with an increase of tumor necrosis factor-alpha, interleukin-1beta concentrations in peripheral blood, and is accompanied by changes in the pituitary-ovarian axis function.

Objective: Cocaine- and amphetamine-regulated transcript (CART) is a recently described neuropeptide widely expressed in the rat brain. CART is abundant in hypothalamus nuclei controlling anterior pituitary function. In the paraventricular nucleus CART mRNA is colocalized with vasopressin and corticotrophin-releasing factor containing neurons. The data may suggest that CART plays a role in hypothalamic regulation of neuroenocrine functions., Material and Methods: Male Wistar-Kyoto rats were investigated. Experiment I: CART was administered intracerebroventricularly (i.c.v.) in a dose of 0.5 microg dissolved in 5 microl vehicle. At 60, 120 min after the infusion of CART or vehicle animals were decapitated and trunk blood was collected until hormonal estimations. Experiment II: CART in a dose of 10 microg was injected intravenously (i.v.). At 60, 120, 240 min the rats were decapitated and the trunk blood was collected. Serum rLH, rFSH, rPRL, rTSH, rGH and plasma leptin, NPY concentrations were measured by RIA methods., Results: CART administered centrally (i.c.v.) simulated significantly GH release after 60 min (p<0.05) and after 120 min (p<0.01). CART increased also PRL after 60 min (p<0.05). A marked increase of corticosterone level was observed at 60 and 120 min (p<0.01, p<0.01). We did not observe significant changes in LH, FSH and TSH. We found an increase of serum leptin concentrations at 60 min after CART administration (p<0.01). However, serum NPY levels did not change. After intravenous injection (i.v.) of CART an increase of GH was observed at 120, 240 min (p<0.01, p<0.01, respectively). A rise in serum PRL was found at 240 min (p<0.05). Corticosterone concentrations were enhanced at 60, 120, 240 min (p<0.01, p<0.01, p<0.01, respectively). We did not observe significant changes in LH, FSH and TSH., Conclusions: CART may play a modulating role in the mechanism of pituitary hormone release.

A series of analogues of hGH-RH-(1-29)-NH2 designed to have metabolic stability has been synthesized. Standard Boc-SPPS was employed, modified to permit the guanidinylation of amino side-chains after chain assembly but before release from the resin. [Dat1, Har(11, 12, 20, 21, 29), Ala15, Nle27, Asp28]-, [Dat1, Har(11, 20, 29), Orn12, Ala15, Nle27, Asp28]-, and [Dat1, Gap(11,12, 21, 29), Ala15, Har20, Nle27, Asp28]-hGH-RH-(1-29)-NH2 were completely resistant to trypsin and about 50 times as potent as hGH-RH-(1-29)-NH2 itself when injected subcutaneously in rats. These peptides are candidates for clinical application in the therapy of GH deficiency.

The effect of repeated and prolonged stress-stimuli applied during 3 days on the plasma prolactin concentration in sheep, in anoestrous, prooestrous and pregnant animals were studied. The following results were obtained: Repeated and prolonged weak electric stimuli applied in the form of footshocks in sheep during 3 days elicited a rise of mesor plasma concentration. The magnitude and the onset of this rise was not associated and dependent on the physiological state of animals. The mesor values of plasma prolactin concentration in all groups of animals except prooestrous ewes on the day following stimulation returned to their prestressing levels. Repeated and prolonged stimuli disturbed circadian rhythm of prolactin secretion existing only in prooestrous ewes, i.e. they caused its disappearance on the days during stimulation and its reappearance on the day following stimulation but at an accelerated and inverse time of the day to that found before stimulation. The induced rise of plasma prolactin concentration in anoestrous and pregnant ewes on the days during electric stimulation showed, according to Cosinor analysis, all features characteristic for acrophase of the circadian rhythm. This phenomenon may be considered as induced acrophase in stress condition.

The effect of 6-hydroxydopamine (6-OHDA) infusion into the third cerebral ventricle on the secretion pattern of prolactin in anoestrous sheep, subjected to repeated and prolonged stress-stimuli was followed. On the 12-15 th day after the infusion of 6-OHDA into the third cerebral ventricle and after having tested the effect of this infusion on plasma prolactin concentration, the animals were subjected to mild electric footshocks 9 hrs daily (9 a.m.-6 p.m.) for 3 consecutive days. Infusion of 6-OHDA induced a very high rise of plasma prolactin values by about 3 times as compared to those found before infusion (from 118.2 +/- 39.5 to 338.9 +/- 81.7 ng/ml mesor 24 h). On the other hand, the response of the animals pretreated with 6-OHDA to electric stimulation was characterized by the lack of changes in plasma prolactin concentration; their plasma hormone concentrations were neither raised during stimulation nor decreased after the stimulation and were maintained during all these days nearly at the same level as after the infusion of 6-OHDA. Central mechanisms which could account for the so high and prolonged elevation of plasma prolactin concentration after the infusion of 6-OHDA and for the lack of its rise under conditions of prolonged stress are discussed.

Diurnal variations in the plasma cortisol level were studied in anoestrous, pro-oestrous and pregnant ewes subjected to weak electric stimulation of the fore-limbs 9 h daily for 3 consecutive days. In non-pregnant ewes the cortisol level rose on each of the 3 days when the stimulation was applied and then decreased on the day following the stimulation. A similar decrease in plasma cortisol concentrations in pregnant ewes appeared on the second day of footshocking. The acrophase of the circadian rhythm on electrostimulation days was synchronous with the time of application of footshocks; therefore, in stimulated ewes it was significantly accelerated compared to the prestimulatory day. A decrease in the plasma cortisol level in pro-oestrous and pregnant ewes was accompanied by disappearance of its normal rhythmicity. Since a normal plasma cortisol response to exogenous corticotrophin was noted after 3 days of footshocking it seems unlikely that the decrease in the cortisol level after prolonged stress was caused by exhaustion of the adrenal cortex. Some central mechanisms which could account for the biphasic changes in the plasma cortisol level and for disturbances of the hormone diurnal rhythmicity under conditions of prolonged stress are discussed.

It has been demonstrated in our previous papers that in the anterior part of medial basal hypothalamus (AM BH) in sheep a stimulating, while in the caudal part of MBH (CMBH) an inhibiting centre of prolactin release are situated. These results suggested that CMBH might be the site of PIF production and prompted us to investigate the effect of dopamine (DA) on the concentration of prolactin in the peripheral blood (p.bl.) in animals in which CMBH had been previously lesioned and this concentration was very high. Microinfusion of L-dopamine into the third cerebral ventricle (c.v.) or into the internal maxillary artery in intact as well as in lesioned lactating ewes depressed distinctly the prolactin level in the p.bl. This action of DA suggests that in the CMBH exists dopaminergic system which itself plays an inhibitory role in the control of prolactin release without involvement of PIF.

It has previously been observed that sheep subjected to repeated and prolonged stress stimuli showed biphasic cortisol responses. On the first and second day of stimulation an elevation was observed, while on the subsequent days and on the day after the stimulation a marked suppression of plasma cortisol level and a disappearance of its circadian rhythm was noted. It was hypothesized that these changes in the secretion of the hormone were caused by the alteration of catecholaminergic systems in the CNS. To verify this suggestion chemical lesions of the catecholergic systems of the diencephalon were carried out by the infusion of 6-hydroxydopamine (6-OHDA) into the third cerebral ventricle and animals treated in this fashion were subjected to repeated and prolonged electrical mild footshocking (applied during 3 days). The pretreated animals lost the circadian rhythm in cortisol secretion on the days before as well as during and after the electrical stimulation. The animals pretreated with 6-OHDA showed a significant rise of the plasma cortisol level during stimulation. This rise, as the highest daily concentration, occurring within about 1 h after the beginning of footshocking, was significantly accelerated in time with respect to the physiological acrophase, occurring in the early morning hours at the end of prestimulatory days. On the other hand, the pretreated animals did not show the decrease of plasma cortisol levels on the day after the stimulation, observed in normal non-pretreated ones.(ABSTRACT TRUNCATED AT 250 WORDS)