Role of thyroid stimulating hormone in the maintenance and functioning of the human corpus luteum.

PURPOSE: To evaluate the impact of high thyroid stimulating hormone (TSH) levels on human granulosa-luteal (hGL) cells. METHODS: hGL cells were isolated from follicular aspirates derived from patients undergoing IVF treatment without any thyroid disorder (serum TSH 0.5-2 mU/L). Cells were cultured at 37 °C in DMEM, supplemented with 5% FBS. The cells were treated with 1 nM LH and increasing concentrations of TSH. At the end of culture, conditioned medium and cells were collected to analyze progesterone production, cell viability, and mRNA levels of genes involved in the steroidogenesis process. Human ovarian tissues were analyzed for TSH receptor (TSHR) expression by IHC. RESULTS: The expression of TSHR was detected in human corpus luteum by IHC and in hGL by RT-PCR. In hGL cells, TSH treatment did not modulate progesterone production nor the expression of steroidogenic genes, such as p450scc and HSD3b 1/2. However, TSH induced a dose-dependent increase in cell death. Finally, TSH did not affect LH-induced p450scc and HSD3b1/2 expression while LH partially reverted TSH negative effect on cell death in hGL. CONCLUSIONS: Elevated TSH levels in hypothyroid women may be associated with impaired CL functioning and maintenance. These findings open a new line of research for the importance of the treatment of women with thyroid dysfunction that could contribute to the onset of infertility.

Prevalence of elevated pulmonary artery systolic pressure in Down Syndrome young patients with and without congenital heart disease.

This study examined the prevalence and distribution of elevated systolic pulmonary arterial pressure, measured by echocardiography, in young patients with down syndrome associated or not with congenital heart disease and surgical correction during childhood. Pulmonary artery systolic pressure, computed by regurgitant tricuspid flow velocity evaluation, is the most frequently used parameter for the screening of pulmonary hypertension. Down syndrome and congenital heart disease often coexist and the probability to detect elevated systolic pulmonary arterial pressure in this setting is high. However, little is known about the evaluation of pulmonary arterial pressure during growth of patients with down syndrome with or without congenital heart disease. We enrolled 47 young patients (55% of male sex; mean age: 18.4 ± 6.0 years), 40 with congenital heart disease and 7 without a cardiac defect. Systolic pulmonary arterial pressure was assessed by echocardiography. No difference was found in the population dichotomized by presence or absence of CHD. Only male sex (p=0.000), highly sensitive troponin-T (P=0.027), tricuspid annular plane systolic excursion (TAPSE, p=0.045) and sPAP (p=0.004) were elevated in surgical group. The ASD was found as, the most common structural abnormality in our patients (50%), followed by VSD (27.5%) and complex CHD (such as complete atrioventricular canal defect, CAVC = 25% and Fallot disease = 15%). Furthermore, about 45% of patients had the combined defect. Only 37.5% of patients underwent to corrective surgery during the first months of life. We observed a significantly increase of sPAP values in patients with complex CHD, such as CAVC (p=0.019) and Fallot disease (p=0.001) but, in the following multivariate analysis performed in the patients with CHD, only Fallot disease remains as independent predictors of elevated values of sPAP (p=0.022). An elevated systolic pulmonary arterial pressure may represent the key screening tool in the diagnostic assessment of suspect pulmonary arterial hypertension in high risk population with down syndrome regardless the presence of congenital heart disease.

"Hormone of darkness" and human reproductive process: direct regulatory role of melatonin in human corpus luteum.

PURPOSE: To investigate the possible role of melatonin on human luteal cell function. METHODS: Corpora lutea were obtained from normally menstruating women (25-38 years old) in the midluteal phase (days 5-6 from ovulation) at the time of surgery for non-endocrine gynecologic diseases. The protocol was approved by the institutional review board of Università Cattolica del Sacro Cuore in Rome and all patients provided written informed consent. The corpora lutea were dated on the basis of the presumptive day of ovulation (day 0) , determined by urinary luteinizing hormone (LH) peak, ultrasound detection of corpus luteum or disappearance of the dominant follicle, and a rise in the plasma P concentration. ELISA or EIA kit and immunohistochemistry were performed. RESULTS: Melatonin was able to increase progesterone release and to influence the balance between luteotrophic and luteolityc factors. In addition, melatonin expression and MT2 receptor were detected, confirming the direct action of this indoleamine on CL. CONCLUSIONS: Melatonin may play an intriguing role in direct regulation of CL function and in establishing and maintaining of initial pregnancy. In conclusion, melatonin could become a relevant medication for improving ovarian and luteal function and in the early stages of pregnancy, opening new opportunities for the management of several ovarian-luteal and pregnancy diseases.

The resting metabolic rate in women with polycystic ovary syndrome and its relation to the hormonal milieu, insulin metabolism, and body fat distribution: a cohort study.

PURPOSE: To evaluate possible alterations of a major determinant of energy expenditure, the resting metabolic rate (RMR), in women with polycystic ovary syndrome (PCOS) compared with age-BMI similar controls. To assess whether the hormonal milieu, the body fat distribution and the insulin metabolism may affect energy consumption in these patients. METHODS: This is a monocentric observational prospective cohort study, including 109 Caucasian PCOS subjects and 31 healthy control women. (Median age PCOS 26.0 ± 9.2 years, controls 25.5 ± 8.5 years; median BMI-body mass index PCOS 26.4 ± 9.4 kg/m2, controls 27.2 ± 12.8 kg/m2). RMR was evaluated by the SenseWear Armband (SWA), a reliable and validated metabolic holter, never previously used in the PCOS population to this purpose. Hormonal assessment, insulin metabolism evaluated by HOMA-IR and OGTT, anthropometric features (BMI and WHR) were also assessed. RESULTS: Median RMR resulted similar in PCOS and control women: 1520.0 ± 248.00 kcal/day vs 1464.0 ± 332.70 kcal/day (p = 0.472), even after adjusting for BMI, fat distribution, insulin metabolism parameters. RMR resulted significantly correlated with BMI, WHR, estradiol levels, SHBG, total cholesterol, triglycerides, basal glycaemia, basal insulinemia, AUC insulin 240', and HOMA. In the subgroup of patients with WHR > 0.85, PCOS women showed a significantly lower RMR compared with controls. CONCLUSIONS: The higher prevalence of obesity, which negatively influences the reproductive and general health of PCOS women, could be related to factors other than an intrinsic alteration of the RMR. Further studies are needed to clarify the possible role of the visceral fat in modulating the energy balance in PCOS. TRIAL REGISTRATION NUMBER: clinicaltrials.gov Identifier NCT03132545.

Increased fibulin-1 plasma levels in polycystic ovary syndrome (PCOS) patients: possible contribution to the link between PCOS and cardiovascular risk.

PURPOSE: To investigate a possible relation between fibulin-1 plasma levels and PCOS. DESIGN: ELISA quantitative determination of human fibulin-1. METHODS: 50 women with PCOS and 40 control patients who attended the Unit of Human Reproductive Pathophysiology, Università Cattolica del Sacro Cuore, Rome, were enrolled. Ultrasonographic pelvic examinations, hormonal profile assays, oral tolerance test OGTT, lipid profile and ELISA quantitative determination of human fibulin-1 were performed. RESULTS: Fibulin-1 levels were found to be statistically significantly higher in PCOS patients than in matched control women. No statistically significant positive correlation was found between fibulin-1 and AUCi, HOMA-IR, total cholesterol, LDL, AMH, androstenedione and FAI, whereas a statistically significant positive correlation was found between fibulin-1 and 17OHP (p = 0.016) in the PCOS group. However, multivariable linear regression analysis showed that 17 OH P did not independently predict fibulin-1 levels (p = 0.089). CONCLUSIONS: Our data could contribute to explain the hypothesized increased cardiovascular risk and vascular damage in patients with PCOS. A better understanding of the cellular and molecular mechanisms involved in cardiometabolic disorders associated with PCOS is mandatory to identify new therapeutic strategies to eventually prevent the progression of cardiovascular diseases in these patients.

The 312N variant of the luteinizing hormone/choriogonadotropin receptor gene (LHCGR) confers up to 2·7-fold increased risk of polycystic ovary syndrome in a Sardinian population.

OBJECTIVE: Polycystic ovary syndrome (PCOS) is a frequent condition, affecting about 15% of women of reproductive age. Because of its familial occurrence, a multifactorial model of susceptibility, including both genetic and environmental factors, has been proposed. However, the identification of genetic factors has been elusive. DESIGN: Case-control study aimed at evaluating possible associations between functionally relevant variants of the luteinizing hormone/choriogonadotrophin receptor gene (LHCGR) and PCOS phenotype. PATIENTS: A total of 198 PCOS and 187 non-PCOS women, aged 14-35 years, of Sardinian origin, were referred to the outpatient clinic of the Department of Obstetrics and Gynaecology of the University of Cagliari (Sardinia). PCOS diagnosis was based on the Rotterdam criteria. MEASUREMENTS: We determined the genotype of ins18LQ, S291N and S312N variants at the LHCGR locus. Genotype was related to the presence or absence of PCOS and to several clinical and biochemical characteristics. RESULTS: The presence of at least one 312N allele was strongly associated with PCOS risk (OR, 2·04; 95% CI, 1·32-3·14; χ(2) , 10·47; P = 0·001). 312N homozygosity was associated with a further risk increase (OR, 2·73; 95% CI, 1·25-5·95; χ(2) , 6·65; P = 0·01). The number of ins18LQ alleles was associated with LH serum levels in controls (χ(2) , 8·04, P = 0·017). CONCLUSIONS: For the first time, we have identified a genetic variant that is strongly associated with PCOS in an isolated population. These results, if confirmed in other cohorts, may provide the opportunity to test the S312N genotype at the LHCGR locus in fertile women to assess the risk of PCOS. The avoidance of triggering factors like weight increase may improve the reproductive outcome of potentially at-risk subjects.

Could antispasmodic drug reduce pain during hysterosalpingo-contrast sonography (HyCoSy) in infertile patients? A randomized double-blind clinical trial.

OBJECTIVE: To assess the effectiveness of an antispasmodic drug, hyoscine-N-butylbromide, in reducing pain during hysterosalpingo-contrast sonography (HyCoSy). METHODS: Eight hundred and sixteen patients undergoing HyCoSy were randomized to receive 10 mg hyoscine-N-butylbromide (n = 408) or placebo (n = 408) per os, 30 min before the procedure, in a double-blind randomized controlled trial. Immediately after the procedure, the patient was asked to describe any pain experienced in comparison with pain usually suffered during the menstrual cycle, and the operator assigned a pain score between 0 and 4 as follows: 0 (no reaction or discomfort), 1 (slight pain, less than menstrual pain), 2 (moderate pain, exceeding menstrual cramps but no vasovagal reaction), 3 (vasovagal reaction or pain requiring observation in a hospital) and 4 (vasovagal reaction or pain requiring resuscitation). The primary aim was to estimate the difference in pain score, considered as a categorical value, between the active arm of the trial and the control group. The secondary aim was to evaluate if pain is related to tubal patency. RESULTS: There was no difference in pain score between the hyoscine-N-butylbromide group and the placebo group (P = 0.807). There was a negative correlation between pain and tubal patency, regardless of treatment group (P < 0.0001). CONCLUSIONS: Administration of 10 mg antispasmodic drug hyoscine-N-butylbromide does not reduce pain in patients undergoing HyCoSy.

Genetics and Gene Therapy in Hunter Disease.

Mucopolysaccharidosis type II or Hunter syndrome is an X-linked lysosomal storage disease caused by a mutation in the gene encoding the lysosomal enzyme iduronate-2-sulfatase. The consequent enzyme deficiency causes a progressive, multisystem accumulation of glycosaminoglycans, which is the cause of the clinical manifestations involving also Central Nervous System for patients with the severe form of disease. The limits of the currently available therapies for Hunter syndrome, hematopoietic stem cell transplantation and recombinant enzyme replacement therapy, mainly regarding brain achievement, have encouraged several studies which recognized gene therapy as a potential therapeutic option for this condition. In vitro studies firstly aimed at the demonstration that viral vector- mediated IDS gene expression could lead to high levels of enzyme activity in transduced cells. The encouraging results obtained allowed the realization of many preclinical studies investigating the utilization of gene therapy vectors in animal models of Mucopolysaccharidosis II, together with a phase I clinical trial approved for Hunter patients affected by the mild form of the disease. Together to in vivo studies in which recombinant vectors are directly administered, systematically or by direct injection into Central Nervous System, also ex vivo gene therapy, consisting in transplantation of autologous hematopoietic stem cells, modified in vitro, into the animal or patient, has been tested. A wider clinical application of the results obtained so far is essential to ensure that gene therapy can be definitively validated as a therapeutic option available and usable for this rare but life-threatening disorder.

Expression and relationship between endothelin-1 messenger ribonucleic acid (mRNA) and inducible/endothelial nitric oxide synthase mRNA isoforms from normal and preeclamptic placentas.

Preeclampsia is a mainly vascular disease of pregnancy, probably caused by an imbalance between vasodilator and vasoconstrictor agents that results in generalized vasospasm and poor perfusion in many organs. Among these factors, endothelin-1 (ET-1), a potent vasoconstrictor, is highly increased in preeclamptic women, while nitric oxide (NO), a vasodilator of human utero-placental arteries, is reduced in the same patients. The present study was designed to investigate the interactions between ET-1 and the NO system in the feto-placental unit; to this purpose we also examined the messenger ribonucleic acid (mRNA) expression of ET-1, inducible NO synthase (iNOS), and endothelial NOS (eNOS) in human cultured placental trophoblastic cells obtained from preeclamptic (PE) and normotensive (NT) pregnancies. We also studied whether exogenous ET-1 may affect the expression of iNOS and eNOS in human placental trophoblastic cells. Interestingly, by Northern blot analysis we observed an increased ET-1 mRNA expression level in PE trophoblastic cells compared to NT trophoblastic cells. Furthermore, exogenous ET-1 (10(-7) mol/L) was able to up-regulate its own mRNA expression in both NT and PE trophoblastic cells. iNOS and eNOS mRNA expression was then detected, by semiquantitative PCR, in both NT and PE trophoblastic cells. PE trophoblastic cells expressed lower iNOS mRNA levels compared with NT pregnancies. On the contrary, eNOS mRNA expression was higher in PE trophoblastic cells than in NT cells. Moreover, in the presence of ET-1 we observed a decrease in iNOS and an increase in eNOS mRNA expression levels in both NT and PE trophoblastic cells compared with the respective untreated cells. In conclusion, we demonstrate that ET-1 expression is increased in PE cells, whereas iNOS, which represents the main source of NO synthesis, is decreased; conversely, eNOS expression is increased. Finally, ET-1 is able to influence its own as well as NOS isoform expression in normal and PE trophoblastic cultured cells. These findings suggest the existence of a functional relationships between ET(s) and NOS isoforms that could constitute the biological mechanism leading to the reduced placental blood flow and increased resistance to flow in the feto-maternal circulation, which are characteristic of the pathophysiology of preeclampsia.

Successful induction of ovulation and conception with combined gonadotropin-releasing hormone agonist plus highly purified follicle-stimulating hormone in patients with polycystic ovarian disease.

Five women (group A) with polycystic ovarian disease (PCOD) and sterility for at least 3 yr were treated for 1 cycle for ovulation induction with a combined regimen of GnRH agonist (GnRH-A) plus highly purified FSH. The patients received GnRH-A (Buserelin; 200 micrograms, sc, twice a day) for 6 weeks and then GnRH-A combined with FSH highly purified (2 ampules a day; 75 IU FSH and less than 0.11 IU LH in each ampule). Ovarian response was evaluated by plasma estradiol (E2) assay and ultrasound examination, performed daily. Furthermore, plasma FSH and LH levels were assayed 3 times a week. Once a follicle was considered sufficiently developed, the combined regimen was withheld, and 24-48 h later hCG (5000 IU, im) was given. The results are compared with those of 31 ovulatory cycles induced by im FSH highly purified (group B) in PCOD patients with the same FSH administration, clinical, and monitoring protocols. Ovulation was achieved in all cycles treated by GnRH-A plus FSH. Two singleton and a twin pregnancy resulted. Multiple follicular development occurred in all cycles. Plasma E2 levels were generally in the normal range. Echographic and endocrine features in the 2 groups were as follows. 1) basal ovarian volume and ovarian enlargement were similar. 2) Group A had a greater number of follicles than did group B (P less than 0.01), while E2 to number of follicles and E2 to ovarian volume ratios were greater (P less than 0.01) in group B. 3) The linear correlations between plasma E2 levels and ovarian volume were markedly different in groups A and B (P less than 0.01). The regression line for group B had a steeper slope than that for group A. This finding indicates that at a fixed ovarian volume plasma E2 levels were significantly lower in group A than in group B. We conclude that the combined GnRH-A and FSH regimen may constitute an alternative and promising tool for the induction of ovulation in patients with PCOD.

In vitro production of plasminogen activator by human granulosa cells.

Plasminogen activator (PA) production by granulosa cells has been demonstrated in several species. In the human ovary, tissue-type PA and urokinase-type PA antigens have been found in the follicular fluids, but neither PA activity nor mRNA for both enzymes was found in granulosa cells of preovulatory follicles. All of these studies were performed on granulosa cells collected from follicles immediately before ovulation, when the cells were already in the luteal phase. In the attempt to better characterize the PA/plasminogen system in the human ovary, we examined PA and PA inhibitor (PAI) production in cultures of granulosa cells obtained from normally cycling untreated women at different stages of the cycle. In addition, we analyzed granulosa-luteal cells obtained from hormonally stimulated women undergoing gamete intrafallopian tube transfer, as a model of late phase follicular development. Zymographic analysis as well as immunoprecipitation with specific antisera revealed that granulosa cells from follicles at early phases of antral stages secreted high levels of PA of the urokinase type in the medium. No free tissue-type PA activity was found in any of the examined samples. On the contrary, free PAI was undetectable in medium obtained from granulosa cell cultures, and it was abundant in granulosa-luteal cell cultures, where it was found in two forms. These data show that in the human ovary as in that of the rat, PAs and PAIs are tightly time regulated. The timing of PA production in human granulosa cells suggests a role for PA activity at early stages of follicular maturation.

Drospirenone for the treatment of hirsute women with polycystic ovary syndrome: a clinical, endocrinological, metabolic pilot study.

The aim of this study was to investigate the effects of the new estro-progestinic containing the antimineralcorticoid progestogen drospirenone (DRSP) in women with polycystic ovary syndrome (PCOS). Fifteen hirsute PCOS patients were treated with 30 microg ethinyl estradiol plus 3 mg DRSP for 12 cycles. Ultrasonographic pelvic exams, evaluation of hirsutism scores, and hormonal and lipid profile assays were performed at baseline and after three, six, and 12 cycles of treatment. An oral glucose tolerance test and euglycemic hyperinsulinemic clamp were also performed, except at the third cycle. The treatment was well tolerated, and all women attained satisfactory cycle control. Hirsutism significantly improved from the sixth cycle onward. Body weight and fat distribution as well as blood pressure remained stable throughout the treatment. Plasma levels of LH, testosterone, SHBG, and, consequently, the free androgen index significantly fell from the third cycle on. Dehydroepiandrosterone sulfate and 17-hydroxyprogesterone significantly decreased after six cycles. The treatment did not affect glycoinsulinemic homeostasis. A trend toward an increase was seen for total cholesterol, triglycerides, and high- and low-density lipoproteins (HDL and LDL) plasma concentrations, although all parameters remained within the normal range. No modifications in total cholesterol/HDL and HDL/LDL ratios were induced by the therapy. The ethinyl estradiol/DRSP combination seems to be effective in ameliorating clinical and hormonal features of PCOS.

The impact of insulin secretion on the ovarian response to exogenous gonadotropins in polycystic ovary syndrome.

The aim of the study was to evaluate the influence of insulin level on the ovarian response to FSH when inducing ovulation in patients affected by polycystic ovarian syndrome (PCOS). To evaluate the presence of hyperinsulinemia, 34 patients affected by PCOS were studied by an oral glucose tolerance test, then patients were stimulated for 52 cycles using FSH to induce ovulation. The ovarian response to therapy was evaluated by ultrasounds and as estradiol (E2) and androstenedione (A) plasma level determinations. On the basis of the insulinemic response to the glucose challenge, 20 patients were considered to be hyperinsulinemic and 14 normoinsulinemic. The hormonal features of each group were similar. The ovulation rate was similar in hyperinsulinemic and normoinsulinemic subjects, whereas the incidence of ovarian hyperstimulation was significantly higher in the hyperinsulinemic group. The increase in ovarian dimensions observed in hyperinsulinemic subjects after gonadotropin stimulation was more marked than that observed in normoinsulinemic ones. This was caused by the development of a larger number of immature follicles. E2 levels gradually increased after gonadotropin stimulation in both groups of subjects; however, higher levels were observed in hyperinsulinemic patients. During stimulation, the higher E2/A ratio suggests the presence of a greater aromatization activity in hyper-insulinemic patients. In conclusion, the present study suggests that, in PCOS, the insulinemic pattern may influence the ovarian response to gonadotropin administration; thus, hyperinsulinemic subjects may be at greater risk of ovarian hyperstimulation syndrome than normoinsulinemic subjects.

Human umbilical vein endothelial cells: a new source and potential target for corticotropin-releasing factor.

Corticotropin-releasing factor (CRF) plays a key role in the modulation of fetal-placental unit function during human pregnancy. CRF has a potent vasoactive action on fetal-placental circulation. As products secreted from endothelial cells affect vascular wall reactivity, we investigated whether cultured human umbilical vein endothelial cells (HUVEC) may represent a source and a target for CRF. With RT-PCR we showed that HUVEC express CRF and CRF receptor type 2 messenger ribonucleic acids. Cultured HUVEC also released CRF peptide in a time-dependent way, and the CRF release was differently regulated by various molecules. Dexamethasone decreased CRF release, whereas progesterone and 17beta-estradiol markedly increased it. Forskolin and PGF2alpha were potent stimulators of CRF release from HUVEC. Among the peptides, CRF secretion was stimulated by interleukin-1beta and by endothelin-1. Our study shows for the first time that HUVEC express CRF messenger ribonucleic acid and peptide as well as the CRF R2 gene, and that CRF release is differentially regulated by several distinct molecules. We here propose that CRF has a role in the regulation of the fetal-placental circulation.

Involvement of ovarian steroids in the opioid-mediated reduction of insulin secretion in hyperinsulinemic patients with polycystic ovary syndrome.

To evaluate the possible involvement of ovarian steroids on the opioid-mediated disorders of insulin in patients affected by polycystic ovary syndrome (PCOS), we studied 40 PCOS women. All patients underwent an oral glucose tolerance test (OGTT; 75 g) and basal hormone assay; based on the insulin response to OGTT, 26 women were classified as hyperinsulinemic and continued the study protocol. Patients were randomly divided into three groups characterized by different treatments: group A (nine patients) was treated with GnRH analog (one ampule every 28 days for 2 months), group B (eight patients) was treated with naltrexone (an oral opioid antagonist, 50 mg/day, orally) for 8 weeks, and group C (nine patients) was treated with GnRH analog plus naltrexone for 2 months. After continuation of treatment, all patients repeated the basal study in a second hospitalization. Naltrexone treatment significantly reduced the insulin response to OGTT, whereas GnRH analogue administration did not significantly change the insulin secretion after the glucose load. The GnRH analog/ naltrexone cotreatment was not able to influence the insulin secretory pattern; in fact, the insulin area under the curve was superimposable before and after therapy. These data could lead to the hypothesis that the opioidergic regulation of insulin secretion requires a normal steroidogenic pattern, thus suggesting that ovarian steroids modulate opioid activity also at peripheric districts.

Evidence for a functional link between the heme oxygenase-carbon monoxide pathway and corticotropin-releasing hormone release from primary cultures of human trophoblast cells.

The gene expression and synthesis of both constitutive and inducible heme oxygenase (HO) isoforms have been recently described in human placental cells, but the functional role(s) of this biochemical pathway in placental physiology and pathology is still unclear. In the present study, we have investigated whether HO activity is involved in the control of CRH secretion from trophoblast cells. Fluctuations in HO activity were induced in primary cultures of human trophoblast cells using well-known activators and inhibitors of HO, and the subsequent changes in CRH secretion were monitored measuring CRH immunoreactivity released into the incubation medium. It was found that the increase in HO activity induced by hemin or cobalt chloride (CoCl(2)) was associated with parallel significant increases in CRH release. This effect was probably caused by the gaseous HO end-product, carbon monoxide (CO), because it was blocked by the HO inhibitor tin-mesoporphyrin-9, but it was not mimicked by stable HO end-products, biliverdin and bilirubin. We have also investigated whether stimulation of CRH release induced by HO was mediated by the cyclooxygenase (COX) pathway. Indeed, hemin also caused significant increases in PGE2 release in this experimental paradigm. However, CoCl(2), which also enhances CRH release, had no stimulatory effect and actually inhibited PG secretion; moreover, a nonselective COX inhibitor, indomethacin, failed to counteract hemininduced CRH release. Taken collectively, these findings suggested that modulation of CRH secretion by the HO-CO system occurs through a mechanism independent of COX activity.

Endothelins enhance prostaglandin (PGE(2) and PGF(2alpha)) biosynthesis and release by human luteal cells: evidence of a new paracrine/autocrine regulation of luteal function.

We have previously shown that endothelin-1 (ET-1) is normally found in human luteal cells, where it is able to significantly inhibit both basal and hCG-induced progesterone production. To further expand our comprehension of the possible roles of endothelins (ETs) in luteal physiology, in this study we used primary cultures of luteal cells exposed to graded doses of ET-1 and ET-3; PGF(2alpha) and PGE(2) were assayed in the culture medium to investigate whether ETs also influence cyclooxygenase activity in these cells. We found that both ETs are able to significantly stimulate PGF(2alpha) and PGE(2) release in a dose- and time-dependent manner. ET-1 was always more effective than ET-3. Experiments with two endothelin receptor antagonists (the BQ485 and BQ788 compounds, which block the ET-A and ET-B receptors, respectively) showed that the two endothelins induce PG production through different receptors and signaling pathways. In conclusion, here we demonstrate the ability of ETs to influence PG synthesis and release from human luteal cells. As PGs are deeply involved in corpus luteum activity, and ETs were also able to influence progesterone production, the present new data suggest an interesting interplay among progesterone, PGs, and ETs in the control of corpus luteum physiology.

Paracrine regulation of insulin-like growth factor I (IGF-I) an IGF-II on prostaglandins F2alpha and E2 synthesis by human corpus luteum in vitro: a possible balance of luteotropic and luteolytic effects.

The existence of a complete intraovarian insulin-like growth factor (IGF) system replete with ligands, receptors, and binding proteins has been demonstrated as well as the ability of IGF-I to positively affect steroidogenesis in human granulosa cells. Furthermore, we recently showed that IGF-I and IGF-II stimulate progesterone secretion by human luteal cells. As the PGs, PGE2 and PGF2alpha, are classically known to have luteotropic and luteolytic effects, we wanted to determine whether the IGFs could affect the human luteal phase by influencing the PG system. For this reason, human luteal cells were cultured for different times (12, 24, and 48 h) with IGF-I, IGF-II (10-100 ng/mL), and GH (100 ng/mL), and both PGs were assayed in the medium culture. We found that both IGF-I and IGF-II were able to stimulate PGE2 synthesis in a time- and dose-dependent way, whereas they both inhibited PGF2alpha production. GH, too, significantly reduced PGF2alpha synthesis; this effect was IGF-I mediated because it was reverted by increasing dilutions of an anti-IGF-I antibody. On the contrary, no GH effect was observed on PGE2 production. In conclusion, based on these data and on our previous results, we speculate that IGFs could influence luteal steroidogenesis through PG system.

Growth hormone induces in vitro maturation of follicle- and cumulus-enclosed rat oocytes.

The aim of this study was to assess the possible role of growth hormone (GH) on rat oocyte maturation. This effect was analyzed in follicle-enclosed, cumulus-enclosed and denuded oocytes obtained from immature pregnant mare's serum gonadotropin (PMSG)-treated rats. The addition of GH to the cultures significantly accelerated maturation in both follicle- and cumulus-enclosed oocytes while no effect was seen on denuded oocytes maturation. Also, GH accelerated meiotic maturation in follicle-enclosed oocytes from immature untreated rats. The GH action was not mediated by lactogenic receptors since prolactin (Prl) did not affect the maturation process while it was mediated by insulin growth factor-I (IGF-I) as suggested by the block of GH action observed in the presence of antibodies anti-IGF-I. Finally, no GH effect was found when dbcAMP was added to the cultures. Our results demonstrate that GH is capable of inducing maturation in oocytes from both primed and unprimed rats. Since the presence of physiological levels of GH in the ovary is now well established, the present data strongly suggest a potential relevance of GH in the reproductive biology.

Growth hormone-releasing factor stimulates meiotic maturation in follicle- and cumulus-enclosed rat oocyte.

This study was designed in order to assess the possible role of growth hormone-releasing factor (GRF) on oocyte maturation. This effect was analyzed in follicle-enclosed, cumulus-enclosed and denuded oocytes obtained from immature pregnant mare's serum gonadotropin-treated rats. The addition of GRF to the cultures significantly accelerated maturation in follicle- and cumulus-enclosed oocytes while no effect was seen on denuded oocytes. Also, the neuropeptide was able to induce maturation in follicle-enclosed oocytes obtained from immature untreated rats. The GRF action was probably not mediated by the vasoactive intestinal peptide (VIP) receptors since the two hormones had different effects on oocyte maturation and on cAMP production by granulosa cells. In addition the disappearance of the GRF effect observed in the presence of antibodies anti-GH suggested that GRF required the intermediacy of GH to accomplish its effect on oocyte maturation. Finally, GRF did not affect meiotic maturation when dbcAMP was added to the cultures. Our results demonstrate the ability of GRF to accelerate maturation in oocytes from both primed and unprimed rats. Since the presence and the involvement of GRF at the ovarian levels is now well established, the present data strongly suggest an important potential role of GRF in the ovarian physiology.