Follistatin as a potent regulator of bone metabolism.

Follistatin is a monomeric glycoprotein, distributed in a wide range of tissues. Recent work has demonstrated that this protein is a pluripotential molecule that has no structural similarity but is functionally associated with members of the transforming growth factor (TGF)-ß superfamily, which indicates its wide range of action. Members of the TGF-ß superfamily, especially activins and bone morphogenetic proteins are involved in bone metabolism. They play an important role in bone physiology, influencing bone growth, turnover, bone formation and cartilage induction. As follistatin is considered to be the antagonist of the TGF-ß superfamily members, it plays an important role in bone metabolism and development.

Interaction between oestrogen and oxytocin on hypothalamic-pituitary-adrenal axis activity.

In addition to its role in reproduction, oxytocin has central actions modulating behavioural and hypothalamic-pituitary-adrenal (HPA) axis responses during late pregnancy and lactation. The hypothesis that ovarian hormones modulate the effects of oxytocin on HPA axis activity was studied in 7-day ovariectomised rats receiving oestradiol with or without progesterone replacement and intracerebroventricular (i.c.v) minipump infusion of oxytocin (100 ng/h). In an initial experiment, i.c.v. oxytocin had no effect on basal or restraint-stimulated plasma adrenocorticotrophic hormone (ACTH) and corticosterone concentrations or hypothalamic corticotrophin-releasing factor (CRF) mRNA expression with low oestradiol replacement alone but it had a stimulatory effect in the presence of low oestradiol and progesterone. To investigate further whether oestradiol modulates central actions of oxytocin, rats received low dioestrous (low), pro-oestrous (medium) or pregnancy (high) oestradiol replacement levels, yielding plasma concentrations of < 5, 17.3 +/- 4.5 and 258 +/- 32 pg/ml, respectively, with or without i.c.v. oxytocin. Oestradiol caused dose-dependent increases in basal plasma ACTH and corticosterone concentrations but decreased the ACTH response to restraint stress. In parallel to the changes in basal plasma ACTH, high oestrogen increased basal CRF hnRNA, CRF mRNA in the paraventricular nucleus and pro-opiomelanocortin (POMC) mRNA in the pituitary gland, while decreasing restraint stress-stimulated levels. Intracerebroventricular administration of oxytocin reduced basal and stress-stimulated plasma ACTH, hypothalamic CRF hnRNA (30 min), CRF mRNA and pituitary POMC mRNA (4 h) levels parallel to the increases induced by elevating plasma oestradiol. The present study demonstrates the converse effects of oestradiol on basal and restraint stress-stimulated basal HPA axis activity, and that the ability of central oxytocin to inhibit HPA axis activity depends on the levels of circulating oestradiol.

Corticotrophin-releasing hormone and ACTH levels in maternal and fetal blood during spontaneous and oxytocin-induced labour.

The changes in corticotrophin-releasing hormone (CRH), ACTH and dehydroepiandrosterone (DHEA) in maternal and fetal plasma were estimated in women undergoing spontaneous and oxytocin-induced labour to correlate hormone changes with the mode of parturition. Blood was sampled from a maternal peripheral vein 2 days before labour, during the second stage of labour and on the second postnatal day, and also from umbilical vessels just after delivery. Hormone concentrations were measured by RIA and ELSA methods. The maternal plasma CRH concentration before labour was significantly higher in the group of women delivered spontaneously and declined during the labour through to the second postnatal day. Measured in umbilical vessels, CRH as well as ACTH concentrations were higher in the umbilical vein than artery. The mean maternal plasma ACTH was similar in both groups before delivery, then increased significantly in both groups during the labour, decreasing on the second day after delivery. There were no changes in DHEA concentrations among the groups and at all time points of collection. No correlations between CRH and ACTH or DHEA were observed. Our results suggest that the maternal pituitary can respond to stress factors during delivery but peripheral CRH, probably mainly of placental origin, is not a major modulator of pituitary action.

Central corticotropin-releasing hormone receptors modulate hypothalamic-pituitary-adrenocortical and sympathoadrenal activity during stress.

The role of brain corticotropin-releasing hormone receptors in modulating hypothalamic-pituitary-adrenal and sympathoadrenal responses to acute immobilization stress was studied in conscious rats under central corticotropin-releasing hormone receptor blockade by intracerebroventricular injection of a peptide corticotropin-releasing hormone receptor antagonist. Blood for catecholamines, adrenocorticotropic hormone and corticosterone levels was collected through vascular catheters, and brains were removed at 3 h for in situ hybridization for tyrosine hydroxylase messenger RNA in the locus coeruleus, and corticotropin-releasing hormone and corticotropin-releasing hormone receptor messenger RNA in the hypothalamic paraventricular nucleus. Central corticotropin-releasing hormone receptor blockade reduced the early increases in plasma epinephrine and dopamine, but not norepinephrine, during stress. Immobilization stress increased tyrosine hydroxylase messenger RNA levels in the locus coeruleus by 36% in controls, but not in corticotropin-releasing hormone antagonist-injected rats. In control rats, corticotropin-releasing hormone messenger RNA and type 1 corticotropin-releasing hormone receptor messenger RNA in the paraventricular nucleus increased after stress (P<0.01), and these responses were attenuated by central corticotropin-releasing hormone receptor blockade. In contrast, central corticotropin-releasing hormone antagonist potentiated plasma adrenocorticotropic hormone responses, but slightly attenuated plasma corticosterone responses to stress. The inhibition of plasma catecholamine and locus coeruleus tyrosine hydroxylase messenger RNA responses to stress by central corticotropin-releasing hormone receptor blockade supports the notion that central corticotropin-releasing hormone regulates sympathoadrenal responses during stress. The attenuation of stress-induced corticotropin-releasing hormone and corticotropin-releasing hormone receptor messenger RNA responses by central corticotropin-releasing hormone receptor blockade suggests direct or indirect positive feedback effects of corticotropin-releasing hormone receptor ligands on corticotropin-releasing hormone expression, whereas additional mechanisms potentiate adrenocorticotropic hormone responses at the pituitary level. In addition, changes in neural activity by central corticotropin-releasing hormone are likely to modulate adrenocortical responsiveness during stress.

Interaction between glucocorticoids and corticotropin releasing hormone (CRH) in the regulation of the pituitary CRH receptor in vivo in the rat.

Acute stress causes biphasic changes in corticotropin releasing hormone (CRH) receptor mRNA expression with an early decrease followed by an increase. However, in the absence of glucocorticoids in adrenalectomized rats, stress results in prolonged CRH receptor (CRH-R) mRNA loss, suggesting that interactions between glucocorticoids and hypothalamic factors are critical for regulation of CRH receptor mRNA. To address this question, CRH binding, type-1 CRH-R mRNA, POMC mRNA and POMC hnRNA expression were measured by binding autoradiography and in situ hybridization in pituitaries from intact and adrenalectomized rats. CRH-R mRNA decreased by 59% 5 h after injection of corticosterone (10 mg s.c.) and returned to basal levels by 18 h, a time when plasma corticosterone concentrations were still elevated, and CRH binding and POMC hnRNA were significantly reduced. Elevations in plasma corticosterone in the range of acute stress by injection of 2 mg s.c. caused CRH-R mRNA expression to return to near basal values by 6 h, after a 52% and 39% decrease at 2 h and 4 h. More transient changes were seen after a single injection of CRH (1 microg), with a 44% decrease in CRH-R mRNA and a 175% increase in POMC hnRNA by 2 h, returning to basal values by 4 h. The transient effect of CRH was not due to clearance of CRH from the circulation or receptor desensitization since CRH receptor mRNA expression also recovered after injection of a higher dose (10 microg) or repeated injections of CRH which caused sustained increases in plasma CRH and pituitary POMC hnRNA levels. CRH injection in adrenalectomized rats decreased CRH-R mRNA for up to 6 h, suggesting that glucocorticoids are permissive for the recovery of CRH-R mRNA. Supporting this hypothesis, simultaneous injection of corticosterone and CRH restored CRH-R mRNA expression by 4 h, and increased CRH binding 4 h and 6 h after injection. The data show that interaction between CRH and glucocorticoids counteracts individual inhibitory effects of these regulators alone, and that such effects are likely to contribute to the regulatory pattern of pituitary CRH receptors during acute stress.

Brain angiotensin II modulates sympathoadrenal and hypothalamic pituitary adrenocortical activation during stress.

Angiotensin II (Ang II) type-1 (AT1) receptors are present in areas of the brain controlling autonomic nervous activity and the hypothalamic-pituitary-adrenal (HPA) axis, including CRH cells in the hypothalamic paraventricular nucleus (PVN). To determine whether brain AT1 receptors are involved in the activation of the HPA axis and sympathetic system during stress, we studied the effects of acute immobilization stress on plasma catecholamines, ACTH and corticosterone, and mRNA levels of CRH and CRH receptors (CRH-R) in the PVN in rats under central AT1 receptor blockade by the selective antagonist, Losartan. While basal levels of epinephrine, norepinephrine and dopamine in plasma were unaffected 30 min after i.c.v. injection of Losartan (10 microg), the increases after 5 and 20 min stress were blunted in Losartan treated rats (P < 0.05 for norepinephrine, and P < 0.01 for epinephrine and dopamine, vs controls). Basal or stress-stimulated plasma ACTH and corticosterone levels were unaffected by i.c.v. Losartan treatment. Using in situ hybridization studies, basal levels of CRH mRNA and CRH-R mRNA in the PVN were unchanged after i.c.v. Losartan. While Losartan had no effect on the increases in CRH-R mRNA levels 2 or 3 h after 1 h immobilization, it prevented the increases in CRH mRNA. The blunted plasma catecholamine responses after central AT1 receptor blockade indicate that endogenous Ang II in the brain is required for sympathoadrenal activation during immobilization stress. While Ang II appears not to be involved in the acute secretory response of the HPA axis, it may play a role in regulating CRH expression in the PVN.

Regulation of pituitary V1b vasopressin receptor messenger ribonucleic acid by adrenalectomy and glucocorticoid administration.

Regulation of the number of pituitary vasopressin (VP) receptors plays an important role in controlling pituitary responsiveness during alterations of the hypothalamic pituitary adrenal axis. The mechanisms regulating these VP receptors were studied by analysis of the effects of adrenalectomy and glucocorticoid administration on V1b receptor (V1b-R) messenger RNA (mRNA) by Northern blot and by in situ hybridization in the rat. Adrenalectomy transiently decreased V1b-R mRNA levels by 18 h (77% and 62% for the 3.7-kb and 3.2-kb bands in the Northern blots, and 50% by in situ hybridization), returning to basal levels after 6 days. The decrease in V1b-R mRNA after 18 h adrenalectomy was fully prevented by dexamethasone (100 microg s.c.) but not by elimination of hypothalamic CRH and VP by paraventricular nucleus lesions or median eminence deafferentation. In sham-operated rats, dexamethasone increased receptor mRNA by 50% after 6 days. In contrast to Sprague-Dawley rats, in Brattleboro rats (di/di), which lack hypothalamic VP, adrenalectomy caused a sustained decrease in V1b-R mRNA levels (<50% of controls by 6 days). The data show that pituitary V1b-R mRNA is positively regulated by glucocorticoids and that the recovery of V1b-R mRNA levels after prolonged adrenalectomy is probably mediated by VP. In addition, the data suggest that the down-regulation of VP binding after long-term adrenalectomy is due to posttranscriptional events rather than to changes in V1b-R mRNA.

Angiotensin II changes inositol-1,4,5-trisphosphate content in the pituitary and hypothalamus but not in cerebral cortex of the rat brain.

The present study was undertaken to investigate the effect of angiotensin II (AngII) on the concentration of inositol-1,4,5-trisphosphate (IP3) and the modulation of AngII action by estradiol in the brain. Our studies were conducted in male rat anterior pituiary, hypothalamus and cerebral cortex with and without previous estradiol treatment. In the cerebral cortex, there were no changes in IP3 content after exposure to AngII. In the anterior pituitary, AngII increased the IP3 concentration at all doses studied. However, in the hypothalamus, AngII decreased the IP3 concentration and its effect was also time dependent. Prior treatment with estradiol intensified the effects of AngII action on IP3 concentrations, in both the pituitary (increase) and hypothalamus (decrease). These results indicate that in the male rat anterior pituitary, AngII increases phosphatidiloinositol hydrolysis, leading to the increased production of the intracellular messenger, IP3. The decrease of IP3 concentration observed in the hypothalamus suggests a different site of AngII action in this region. We also suggest that estrogens can modulate AngII action in the brain.

Somatostatin-14 increases the inositol-1,4,5-trisphosphate content in various areas of the brain.

The effects of somatostatin-14 on inositol-1,4,5-trisphosphate (IP3) content were examined in rat pituitary, hippocampus and cortex homogenates. Somatostatin increased IP3 concentration in all these investigated regions in a dose- and time-dependent manner. Maximal increase of IP3 content was found in the pituitary homogenate, and in the hippocampal and cortex homogenates the IP3 argumentation was slightly smaller. Time-response studies showed that this effect declined with extended time of incubation. These results suggest that IP3 is involved in the mechanism of action of somatostatin in brain.

[Evaluating the effect of smoking tobacco on some semen parameters in men of reproductive age]. / Ocena wplywu palenia tytoniu na niektóre parametry nasienia mezczyzn w wieku rozrodczym.

Seminal fluid indexes (sperm count, motility, pH, morphology) were examined in 40 smokers and 30 nonsmokers. The sperm count and motility were lower in smokers. Smokers have also higher incidence of oligospermia compared to nonsmokers. There was no difference between pH and sperm morphology in smokers and nonsmokers. Additionally, smokers have higher levels of endogenous 17 beta-estradiol and sperm count below normal in nonsmokers. These results suggest that inveterate smoking can diminish fertility in men.

[Examining the effects of tobacco smoking on levels of certain hormones in serum of young men]. / Badania nad wplywem palenia tytoniu na stezenie wybranych hormonów w surowicy krwi u mlodych mezczyzn.

Dehydroepiandrosterone (DHEA), testosterone (T), 17 beta-estradiol (E), prolactin (PRL) and gonadotropins (FSH, LH) were examined in 30 smokers and 25 nonsmokers. The mean E level was higher in smokers than nonsmokers, whereas the levels of T and DHEA are similar and did not differ significantly in smokers compared to nonsmokers. Smokers have also lower mean levels of LH, FSH and PRL than nonsmokers. However, smokers with low prolactin levels have also low sperm percent motility, these results suggest that changes in endocrine profile due to cigarette smoking can reduce the fertility.

[Evaluation of semen quality after freezing at the temperature of liquid nitrogen using a modification of two different methods]. / Ocena jakosci nasienia po zamrozeniu w temperaturze cieklego azotu przy zastosowaniu modyfikacji dwõch rõznych metod.

Spermatozoon survival rate was analysed after freezing at the temperature of liquid nitrogen (-196 degrees C) with the application of three different cryoprotector substances, vitelline and non-vitelline. A modified method, based on the use of sperm cells of small diameter, was introduced in freezing semen. The best results were achieved while using non-vitelline, multi-ionic cryoprotector. It was found out that glycerol alone does not protect semen from the effects of low temperature.

[Cooperation of the physician--gynecology and psychology in treating infertility]. / Wspólpraca lekarza--ginekologa i psychologa w leczeniu nieplodnosci.

The paper gives an overview of basic principles of cooperation between gynaecologists in infertility treatment. The authors experience in dealing with patients requesting donor insemination is presented. The outline of psychological consultation in such cases is given.

[Does treatment with antiestrogens in men with oligozoospermia influence the course of pregnancy in infertile married women]. / Czy leczenie antyestrogenami nieplodnosci meskiej wplywa na przebieg ciazy u kobiet z nieplodnoscia malzenska.

Study aimed at obtaining answer to the question if antiestrogenic treatment (tamoxifen or clomiphene) of men having oligozoospermia has an impact on the pregnancy course. The pregnancy courses were live analysed of 34 healthy women, who had been treated with the artificial insemination by husband, having received tamoxifen or clomiphene. No important distinction in the pregnancy courses were found. Delivery at term took place more frequently in the first group than in the second one. There were insignificantly more frequently births of males in both groups.

[X-ray diagnosis of the female reproductive organs using the authors' method]. / Rentgenowska diagnostyka narzadów plciowych z zastosowaniem metody wlasnej.

The authors describe their own method of the dynamic hysterosalpingography using the self-constructed hydraulic hystero-infusing pump. The diagnostic procedure's remote control system allows to avoid superfluous of radiation.