Plasma concentrations of inhibin a and follicle-stimulating hormone differ between cows with two or three waves of ovarian follicular development in a single estrous cycle

Patterns of ovarian follicle development were monitored daily in Holstein-Friesian cows that had two (n = 4) or three (n = 4) waves of ovarian follicle development during a single estrous cycle. The plasma from daily blood samples was used in assays for inhibin A, FSH, progesterone, and estradiol-17beta. Mean cycle lengths for cows with two and three waves were 21.8 and 25.3 days, respectively (P < 0.02). Although the average number of follicles >3-mm diameter on each pair of ovaries was similar for two- and three-wave cows on Days 2, 3, and 4 (Day 0 = day of ovulation; 8.6 vs. 9.6 follicles), there were more follicles >6-mm diameter on the ovaries of cows with two waves on Days 3 and 4. This difference was associated with a shorter interval from wave emergence to peak concentrations of inhibin A during the first wave in two-wave cows (2.0 vs. 3.8 days; P = 0.03) and with higher peak concentrations (474 vs. 332 pg/ml; P = 0.03). Differences in peak FSH concentrations were not significant (1.7 vs. 1.3 ng/ml; P = 0.10) and were inversely related to inhibin A concentrations. The peak concentrations of inhibin A and FSH in the second nonovulatory wave in the three-wave cows were similar to the low concentrations measured in the first wave (292 vs. 332 pg/ml of inhibin A, 1.3 vs. 1.3 ng/ml of FSH; P > 0.20). Average peak concentrations of inhibin A and FSH were similar during the ovulatory wave for cows with either two or three waves in a cycle (432 vs. 464 pg/ml of inhibin A, 2.3 vs. 2.1 ng/ml of FSH; P > 0.3). The lower concentrations of FSH during the emergence of the first follicular wave in cows with three-wave cycles may have reduced the rate of development of some of the follicles and reduced the concentrations of inhibin A. This pattern of lower concentrations of FSH and inhibin A was repeated in the second nonovulatory wave but not in the ovulatory wave. Subtle differences in the concentrations of these two hormones may underlie the mechanism that influences the number of waves of ovarian follicle development that occur during the bovine estrous cycle.     

Immunoactive inhibin as a marker of Sertoli cell function following cytotoxic damage to the human testis

Sertoli and Leydig cell functions were evaluated in men with testicular damage due either to cytotoxic chemotherapy (CCT) or radiotherapy (XRT). Serum immunoactive inhibin, follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone concentrations were measured in 15 men (19-50 years) who had received 6-10 courses of combination CCT (mustine, vinblastine, procarbazine and prednisolone) for Hodgkin's disease 1-8 years earlier and 18 men (21-49 years) who had undergone unilateral orchidectomy for testicular seminoma followed by XRT (30 Gy) to the remaining testis, 1-4 years earlier. Normal men (n = 16, 19-36 years) acted as controls. Median inhibin (422 U/l) and testosterone (16.0 nmol/l) levels in the CCT-treated group were not significantly different from controls, whereas median FSH (14.5 IU/l) and LH (10.0 IU/l) levels were higher (p less than 0.0001 and p less than 0.001) than normal (2.9 and 5.5 IU/l). The median inhibin/FSH (I/FSH) ratio in the patients was lower (p less than 0.0001) than in the controls (33.8 vs. 187.0) as was the testosterone/LH (T/LH) ratio (1.7 vs. 3.8, p less than 0.001). In the XRT-treated group, both median inhibin (194.5 U/l) and testosterone (12.7 nmol/l) levels were lower (p less than 0.0001 and p less than 0.01) than normal (532.8 U/l and 20.0 nmol/l) in the presence of greatly elevated FSH (26.0 IU/l) and LH (14.5 IU/l) levels. In conclusion, CCT-induced testicular damage is associated with subtle Sertoli and Leydig cell dysfunction demonstrated by the reduced I/FSH and T/LH ratios; however, compensatory mechanisms maintain normal testosterone and inhibin levels.(ABSTRACT TRUNCATED AT 250 WORDS)     

Serum inhibin A and inhibin B in central precocious puberty before and during treatment with GnRH agonists

Serum levels of the gonadal hormones inhibin A and inhibin B are undetectable or low in prepubertal girls, and rise during puberty. In girls with central precocious puberty (CPP) the hypothalamic-pituitary-gonadal axis is prematurely activated, if the girl is thereafter treated with GnRH agonists both gonadotropins and estradiol levels become suppressed. We therefore investigated serum levels of inhibin A and inhibin B in girls with CPP at diagnosis and during treatment in order to test the hypothesis that inhibin secretion would increase and decrease in parallel with the activation and suppression of the hypothalamic-pituitary-gonadal axis. Serum levels of inhibin A and inhibin B were significantly (p < 0.0005) elevated in 42 girls at diagnosis of CPP (inhibin A: 7 pg/ml (<7--139), inhibin B: 80 pg/ml (<20--294) (median, range)) compared to levels in age-matched healthy schoolgirls (inhibin A: all values <7 pg/ml, inhibin B: 21 pg/ml (<20--122) (median, range)), but were appropriate for Tanner stage. During treatment with GnRH agonist (intranasal buserelin and oral cyproterone acetate, treatment group 1, n = 23, or triptorelin depot injections, treatment group 2, n = 19) levels of both hormones fell significantly (p = 0.002). There was a significantly (p = 0.003) greater fall in inhibin B levels during treatment in group 2 compared to group 1, with inhibin B levels now lying below (group 2: <20 pg/ml (<20--68)) rather than within (group 1: 34.5 pg/ml (<20--93)) the age-appropriate range. It is concluded that levels of inhibin A and inhibin B are elevated and suppressed in concert with activation and suppression of the hypothalamo-pituitary-gonadal axis in girls with CPP, supporting the concept that ovarian inhibin secretion is dynamically regulated by gonadotropin stimulation.     

Intérêt du dosage de l’inhibine B et de l’AMH dans le plasma séminal: étude préliminaire

Objectives

The aim of this study was to establish reference values for seminal inhibin B and AMH concentrations in patients with normal and abnormal sperm parameters. Preliminary analysis was performed to evaluate the predictive value of these markers for retrieving testicular sperm in non-obstructive azoospermic men.

Methods

Seminal inhibin B and AMH concentrations were assayed by an enzyme-linked immunoassay in three groups of men: 47 patients with normal sperm parameters, 28 oligospermic men and 68 patients with azoospermia.

Results

Inhibin B and AMH concentrations varied considerably in the three groups, but were significantly higher in normospermic men (inhibin B: 714.36±522.66 ng/l, AMH: 97.08±135.15 pmol/l) than in oligospermic men (inhibin B: 417.5±386.9 ng/l, AMH: 62.02±93.33 pmol/l) and azoospermic men (59.61±2.65 ng/l et 13.12±31.94 pmol/l, respectively) (p<0.001). A significant correlation (p=0.0054) was observed between seminal inhibin B concentration and sperm production. Testicular biopsy allowed sperm retrieval in 11 out of 21 patients (52.3%). The predictive value of seminal inhibin B was analyzed using receiver operating characteristics (ROC) curve analysis. The best discriminating inhibin B concentration was 30 ng/l with an area under the curve (AUC) of 0.63.

Conclusion

This study confirms the correlation between seminal inhibin B and AMH concentrations and spermatogenesis. However, the significance of these two markers as predictors of the presence of testicular sperm in men with non-obstructive azoospermia is limited. This analysis shows that AMH and inhibin B, either alone or in combination with serum FSH, fail to predict the presence of sperm in men with non-obstructive azoospermia undergoing testicular sperm extraction.     

Plasma inhibin A in heifers: relationship with follicle dynamics, gonadotropins, and steroids during the estrous cycle and after treatment with bovine follicular fluid

The relationship between follicle growth and plasma inhibin A, FSH, LH, estradiol (E), and progesterone was investigated during the normal bovine estrous cycle and after treatment with steroid-free bovine follicular fluid (bFF) to arrest follicle development. In the first study, four heifers were monitored over three prostaglandin (PG)-synchronized cycles. Blood was collected every 2-8 h, and ovaries were examined daily by ultrasonography. Inhibin A was measured using a modified enzyme-linked immunosorbent assay that employed a new monoclonal antibody against the alpha subunit of bovine inhibin. Plasma inhibin A ( approximately 50 pg/ml before luteolysis) rose steadily during the induced follicular phase (P < 0.05) to a peak ( approximately 125 pg/ml) coincident with the preovulatory E/LH/FSH surge. After ovulation, inhibin A fell sharply (P < 0.05) to a nadir ( approximately 55 pg/ml) coincident with the secondary FSH rise. During the next 3 days, inhibin A increased to approximately 90 pg/ml in association with growth of the new dominant follicle (DF). Plasma E also rose twofold during this period, whereas FSH fell by approximately 50%. Inhibin A was negatively correlated with FSH (r = -0.37, P < 0.001) and positively correlated with E (r = 0.49, P < 0.0001). Observations on eight cycles (two cycles/heifer), in which growth of the ovulatory DF was monitored from emergence to ovulation, showed that the first-wave DF (DF1) ovulated in three cycles and the second-wave DF (DF2) in five cycles. After PG, plasma inhibin A and E increased similarly in both groups, with concomitant falls in FSH. In the former group, the restricted ability of DF1 to secrete both inhibin A and E was restored after luteolysis. Results indicate that dynamic changes in the secretion of both E and inhibin A from the DF contribute to the fall in FSH during the follicular phase and to the generation and termination of the secondary FSH surge, both of which play a key role in follicle selection. In the second study, bFF (two dose levels) was administered to heifers (n = 3-4) for 60 h starting from the time of DF1 emergence. Both doses suppressed FSH (P < 0.05) and blocked DF1 growth to the same extent (P < 0.01), although inhibin A levels were only marginally raised by the lower dose (not significant compared to controls). The high bFF dose raised (P < 0.001) inhibin A to supraphysiological levels ( approximately 1 ng/ml). A large "rebound" rise in FSH occurred within 1 day of stopping both treatments, even though the inhibin A level in the high-dose bFF group was still approximately threefold higher than that in controls. This indicates that desensitization of gonadotropes to inhibin negative feedback is a contributory factor, together with reduced ovarian output of E, in generation of the post-bFF rebound in FSH.     

Gonadotropins at menopause: the influence of obesity, insulin resistance, and estrogens

Obese, postmenopausal women have lower FSH levels. To determine whether this is due to higher estrogen exposure, we compared feedback gonadotropin sensitivity and its relation to insulin resistance in four groups of obese and lean, postmenopausal women. Group one was treated with 400 mg troglitazone (TG) daily for two weeks; 150 clomiphene citrate (CC) was added daily for the second week. Group two received 150 mg CC daily for a week. Group three received 1000 mg metformin (MET) daily for two weeks, with 120 mg raloxifene (RAL) added during the second week. Group four received 120 mg RAL for a week. Before and after each period, a serum pool was obtained from samples taken every minute during a 10 ml interval. The women recruited for this study were categorized as obese or lean based on BMI >/= 29 or BMI < 29, respectively. Obese, menopausal women had lower FSH (45.5 IU/l) and LH (16.2 IU/l) values than those of lean (64.1 IU/l and 23.0 IU/l), but the obese menopausal women had higher leptin, DHEAS, glucose, insulin, and HOMA-IR levels. Log [FSH] was associated with BMI (r = -0.53, P < 0.000001) and number of pregnancies (r = -0.37, P = 0.0009). TG treatment did not change HOMA-IR or gonadotropin levels, but DHEAS and androstenedione levels decreased significantly. CC alone or together with TG, diminished FSH (-7.9 and -9.2) and LH (-2.5 and -3.6) concentrations, with a greater reduction in lean women. MET reduced glucose and the HOMA-IR index without affecting gonadotropin or steroid levels. Conclusions: obese, menopausal women have lower FSH levels due to greater estrogen exposure, by mechanisms unrelated to insulin resistance.     

Anti-Müllerian hormone (AMH) is a strong predictor of live birth in women undergoing assisted reproductive technology

In the present study, we evaluated the clinical value of the following parameters: basal anti-Müllerian hormone (AMH), follicle-stimulating hormone (FSH), inhibin B and antral follicle count (AFC) in predicting live birth outcomes. The study involved 603 women undergoing in vitro fertilization (IVF) using the long protocol for controlled ovarian hyperstimulation (COH). Serum levels of AMH, FSH and inhibin B as well as AFC were measured on the first three days of the menstrual cycle prior to the beginning of stimulation. AMH was the only independent parameter that correlated with the chance of live birth. We found that live birth rates of 46.2% (patient age <35 years), 44.7% (35–37 years), 32.1% (38–39) and 15.3% (>39) were associated with concentrations of AMH > 1.4 ng/ml. For the AMH range 0.6–1.4 ng/ml, the live birth rates were 29.3%, 12.5%, 5.6% and 2.7%, respectively, and for AMH concentrations below 0.6 ng/ml the rates were 7.1%, 8.3%, 0% and 5.8%, respectively. Independently of other parameters affecting the chance of live birth, the success rate was the highest when the AMH level was >2 ng/ml, significantly lower when the AMH concentration was about 1 ng/ml, and 0% when the AMH concentration was ∼0.1 ng/ml. In conclusion, this is the first report to demonstrate that AMH level correlated better than age, FSH or inhibin B concentrations or AFC with live birth outcome. Therefore, the basal serum concentration of AMH may become a new, substantial prognostic factor regarding live birth above and beyond other currently available predictors of IVF outcome.     

Changes in plasma inhibin levels following pulsatile gonadotrophin-releasing hormone therapy in a man with idiopathic hypogonadotrophic hypogonadism

Changes in circulating inhibin levels were related to changes in testosterone (T) and the gonadotrophins luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in a hypogonadotrophic hypogonadal man before and during pulsatile gonadotrophin-releasing hormone therapy which resulted in normal spermatogenesis. Before treatment, the plasma inhibin levels in the patient (210 +/- 50 U/l; mean +/- SD of four samples) were lower than in normal controls (552 +/- 150 U/l; p less than 0.01), as were T (1.1 nmol/l) and gonadotrophin (less than 1.0 IU/l) levels. Within 1 week of gonadotrophin-releasing hormone treatment, plasma LH (14.1 +/- 0.7 IU/l) and FSH (14.4 +/- 0.6 IU/l) reached supraphysiological levels. In response, T and inhibin concentrations increased progressively to reach high normal levels (27.7 +/- 1.6 nmol/l and 609 +/- 140 U/l) at 4 weeks, by which time the gonadotrophin levels stared to decline and gradually returned to the normal range between 12 and 24 weeks of treatment. There was a concomitant decrease in T and inhibin levels which remained within the normal range. The decline in the FSH level following the rise in testicular hormones was earlier and steeper than that of LH (37.5% decrease at 4 weeks vs. 30.4% at 12 weeks), suggesting that T and inhibin may act together to inhibit pituitary FSH secretion as opposed to LH secretion which is primarily controlled by T. It is concluded that, in man, during maturation of the pituitary-testicular axis, changes in circulating inhibin parallel those of T, and quantitatively normal inhibin secretion is dependent on gonadotrophin stimulation. FSH secretion may be regulated through negative feedback control, by both T and inhibin.     

生殖激素对小鼠胚胎性别影响的研究(简报)

性别控制是人类很早就关心的研究领域,因为许多重要的经济性状与性别有直接关系。在家畜生产中,性别控制应用潜力很大,可以大幅度提高生产力,节约生产成本。性别控制可使肉用家畜多产雄性后代,乳用家畜多产雌性后代。为了达到控制     

Gonadotrophin determination in 24-h-urine by sensitive LH and FSH radioimmunoassays.

Urinary Lutropin (LH) and Follitropin (FSH) were precipitated with acetone and measured by specific radioimmunoassays. Recovery experiments with special regard to urinary pH values were done by adding 125I-labelled LH and FSH to unprocessed urine. At pH 4.5 68.6% of LH and 66.1% of FSH were recovered. Increasing pH values up to 6.0 resulted in a significant recovery loss of 125-I-LH, but not of 125I-FSH. Immunoreactive FSH concentrations decreased significantly 6 and 48 hours after storage began at room temperature. In healthy males and females we found mean LH and FSH concentrations in 24-h-urine which were similar to those reported by others: LH: males: 22.6 IU/24-h; cycling females: 17.8 IU/24-h; postmenopausal females: 49.1 IU/24-h; FSH: males 6.0 IU/24-h: cycling females: 15.0 IU/24-h; postmenopausal females: 48.5 IU/24-h. Because of their high sensitivity and practicability, we believe that these radioimmunoassays are clinically useful approaches in assessment of pituitary and gonadal disorders in human subjects.     

Inhibin B levels in adolescents and young adults with type 1 diabetes

OBJECTIVE/METHODS: To assess exocrine and endocrine testicular function in subjects with diabetes, we evaluated serum inhibin B, gonadotrophins and testosterone levels in 33 male adolescent and young adult patients affected by type-1 diabetes (age 21.0 +/- 5 years; range 14.2-33.3), with a mean disease duration of 12.7 +/- 5.8 years (range 1.5-25.3) and various metabolic control (HbA1c 7.8 +/- 1.5%; range 5.5-13.2) and compared them with those of an age-matched group of 36 healthy control subjects (age 19.5 +/- 4.1 years; range 13.6-28.1). Both patients and controls had a testicular volume >or=15 ml. Inhibin B was measured by ELISA method. RESULTS/CONCLUSION: Diabetics and controls had comparable inhibin B (203 +/- 74 vs. 221 +/- 69 pg/ml, respectively) and follicle-stimulating hormone (FSH) levels, while luteinizing hormone (LH) and testosterone levels were significantly higher in the diabetic group. Inhibin B was negatively correlated both in patients and controls with FSH, while a negative correlation with LH was found only in the diabetic group. We conclude that our young diabetic males, after a mean disease duration of 12 years and various metabolic control, had inhibin B and FSH levels comparable to those of normal subjects. Therefore, they seem to have a regular testicular function and in particular a normal seminiferous tubule/Sertoli cell activity despite sustained hyperglycemia.     

Maintenance of a normal meal-induced decrease in plasma ghrelin levels in children with Prader-Willi syndrome.

Ghrelin is a 28-amino acid peptide recently identified in the stomach as the endogenous ligand for the growth hormone secretagogue receptor (GHS-R1a). Ghrelin is a potent stimulator of GH secretion. It was recently shown that circulating ghrelin levels in humans rise shortly before and fall shortly after every meal, and that ghrelin administration increases voluntary food intake. The hypothesis that ghrelin hypersecretion might contribute to genetic obesity has never been investigated. In this context, Prader-Willi syndrome is the most common form of human syndromic obesity. As ghrelin affects appetite as well as GH secretion and both are abnormal in PWS, it has been surmised that these alterations might be due to ghrelin dysregulation. The aim of the study was to investigate whether ghrelin is suppressed by the meals differently in PWS children than in PWS adults. Overnight circulating fasting ghrelin levels and ghrelin levels 120 min after breakfast were assayed in 7 PWS children (10.2 +/- 1.7 yr), 7 subjects with morbid obesity (10.3 +/- 1.3 yr), and 5 normal controls (8.4 +/- 1.4 yr). Because of the data spread, no statistical difference was observed in fasting ghrelin levels between PWS and control children (p = NS); anyway, fasting ghrelin levels were significantly lower in obese children than in the other groups (p < 0.05 vs. control and PWS children). Ghrelin levels were slightly suppressed by the meal in control subjects (mean fasting ghrelin: 160.2 +/- 82 pg/ml; after the meal, 141.2 +/- 57 pg/ml, p = NS); the meal failed to suppress ghrelin levels in obese children (mean fasting ghrelin: 126.4 +/- 8.5 pg/ml; after the meal, 119.1 +/- 8.3 pg/ml, p = NS). Interestingly, the meal markedly suppressed ghrelin levels in PWS children (mean fasting ghrelin: 229.5 +/- 70.4 pg/ml; after the meal, 155.8 +/- 34.2 pg/ml, p < 0.01). In conclusion, since a lack of decrease in circulating ghrelin induced by the meal was previously reported in PWS adults, the finding of a meal-induced decrease in ghrelin levels in our population of young PWS would imply that the regulation of the ghrelin system involved in the orexigenic effects of the peptide is operative during childhood, although it progressively deteriorates and is absent in adulthood when hyperphagia and obesity progressively worsen.     

Ovarian response,embryo production and hormonal profile in superovulated goats treated with insulin

The influence of insulin on ovarian response and embryo production was investigated in 30 mixed breed goats, divided randomly into three equal (n=10) groups. Goats in Group 1 (control) were superovulated using 20 IU FSH i.m. in six divided descending doses, i.e. 4/4, 3/3 and 3/3 IU at 12 h interval for three consecutive days and were not given insulin treatment. Goats in Group 2 (insulin pretreatment) were pretreated with long acting purified bovine insulin 0.2 IU/kg body weight per day s.c. on Days 7, 8 and 9 of the estrous cycle prior to initiation of superovulatory treatment as in Group 1. Animals in Group 3 (insulin cotreatment) were treated as in Group I, but in addition received long acting purified bovine insulin 0.2 IU/kg body weight per day s.c. as a cotreatment along with the first, third and fifth FSH treatments on three consecutive days. Total ovarian response (corpus luteum and unovulated large follicle (UOLF)) was significantly (P<0.05) higher in insulin pretreatment (17.90+/-3.08) than in the cotreatment (11.50+/-2.34) and control (11.90+/-1.87) groups. The number of UOLF was significantly higher (P<0.05) in the insulin pretreatment (10.2+/-1.67) than the cotreatment (4.9+/-1.14) and control (3.6+/-1.09) groups. The mean transferable quality of embryos did not differ significantly among treatments. Progesterone concentration on the day of PGF(2)alpha treatment was not different (P>0.05) between the insulin treatment groups (5.28+/-0.79; 5.30+/-0.66 ng/ml). Estradiol-17beta concentration was significantly (P<0.05) higher on the day of PGF(2)alpha treatment in both the insulin treatment groups (36.67+/-6.40; 34.33+/-4.33 pg/ml) as compared to the control group (20.00+/-2.73 pg/ml). There is ample evidence to indicate beneficial effect of insulin on folliculogenesis and steroidogenesis in superovulated goats.     

Inhibin B,follicle stimulating hormone,luteinizing hormone,and estradiol and their relationship to the regulation of follicle development in girls during childhood and puberty

Inhibin B, produced by granulosa cells in the ovary, is a heterodimeric glycoprotein suppressing synthesis and secretion of the follicle stimulating hormone (FSH). The aim of the present study was to determine hormone profiles of inhibin B, FSH, luteinizing hormone (LH), and estradiol in girls during childhood and puberty and to evaluate whether inhibin B is a marker of follicle development. We examined the correlation between inhibin B and gonadotropins and estradiol during the first two years and across the pubertal development. Using a specific two-side enzyme-linked immunosorbent assay (ELISA), inhibin B levels were measured in the serum of 53 healthy girls divided into 8 groups according to age. In addition, serum FSH, LH, and estradiol were measured by chemiluminescent immunoassay in all serum samples. A rise in serum levels of inhibin B (55.2+/-7.3 ng/l, mean +/- S.E.M.) and FSH (1.78+/-0.26 UI/l), concomitant with a moderate increment of serum LH (0.36+/-0.09 UI/l) and estradiol (45.8+/-12.2 pmol/l) concentrations was observed during the first three months of life and declined to prepubertal concentrations thereafter. A strong positive correlation between inhibin B and FSH (r = 0.48, p<0.05), LH (r = 0.68, p<0.001) and estradiol (r = 0.59, p<0.01) was demonstrated during the first 2 years of life. A rise in serum levels of inhibin B, FSH, LH, and estradiol was found throughout puberty. Inhibin B had a strong positive correlation with FSH (stage I of puberty: r = 0.64, p<0.05; stage II of puberty: r = 0.86, p<0.01), LH (I: r = 0.61, p<0.05; II: r = 0.67, p<0.05), and estradiol (II: r = 0.62, p<0.05) in early puberty. From pubertal stage II, inhibin B lost this relationship to gonadotropins and estradiol. Serum inhibin B and FSH levels increased significantly during pubertal development, with the highest peak found in stage III of puberty (133.5+/-14.3 ng/l), and decreased thereafter. In conclusion, inhibin B is produced in a specific pattern in response to gonadotropin stimulation and plays an important role in the regulation of the hypothalamic-pituitary-gonadal axis during childhood and puberty in girls. Inhibin B is involved in regulatory functions in developing follicles and seems to be a sensitive marker of ovarian follicle development.     

Changes in peripheral inhibin levels and follicular development following treatment of buffalo with PMSG and Neutra-PMSG for superovulation

Fourteen buffalo were synchronized by administration of a prostaglandin (PG) salt Lutalyse in a double injection schedule, with a single intramuscular (im) injection of 25 mg at Day -13, followed by 30 mg and 20 mg im 12 h apart on Day 0 of the experiment. The 30-mg PG injection was designated as 0 h of the experiment. Group I animals (n = 4) received saline and served as the controls, while animals in Groups II and III (n = 5 each) received PMSG (2500 IU im at -48 h. Group III animals were administered 5 ml Neutra-PMSG intravenously at 60 h. Blood samples were collected every 48 h from Day -12 to Day -4, every 24 h from Day -4 to Day 0, every 3 h from Day 1 to Day 4 and every 24 h from Day 5 to Day 10 of experiment for the measurement of peripheral plasma inhibin concentrations by RIA. The number of large follicles (> 10 mm diameter) in animals of Groups II and III was assessed by ultrasonography on Days -2, -1, 0, 1, 2, 5 and 7 of the experiment. Treatment with PMSG of Group II animals resulted in a significant increase (P < 0.05) in plasma inhibin concentrations over that of control animals of Group I at 24 to 99 h, with a peak inhibin concentration of 1.01 +/- 0.31 ng/ml at 48 h. Treatment with Neutra-PMSG in Group III animals caused a significant reduction (P < 0.05) in the peripheral inhibin concentrations at 84 to 120 h and in the number of large unovulated follicles at 168 h compared with that in Group II animals. Peripheral inhibin levels in Group III animals came down to those of Group I after 21 h of Neutra-PMSG treatment. These results suggest that treatment of buffalo with PMSG for superovulation causes a marked rise in peripheral inhibin concentrations. Administration of Neutra-PMSG after PG treatment reduces the peripheral inhibin concentrations and the number of large unovulated follicles.     

17beta-estradiol regulation of human growth hormone (hGH), insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3) axis in hypoestrogenic, hypergonadotropic women

OBJECTIVE: Ovarian hormonal function may be as important contributing factor to hGH-IGF-I-IGFBP-3 axis as age. AIM: To examine plasma hGH, IGF-1 and IGFBP-3 levels in women with premature ovarian failure compared to healthy normal controls and postmenopausal ones. PATIENTS: Group A-15 women with premature ovarian failure (POF) (mean: age 38.9+/-5.2 years, FSH 101.4+/-29.0 IU/l; 17beta-estradiol 22.5+/-14.6 ng/l). Group B consisted of 15 menopausal women (mean: age 54.7+/-2.7 years; FSH 81.9+/-32.1 IU/l; 17beta-estradiol 17.1+/- 8.0 ng/l). Group C - controls - 15 normally menstruating women (mean: age 37.1+/-9.0 years; FSH 6.2+/-1.0 IU/l; 17beta-estradiol 144.8+/-117.1 ng/l). METHODS: Body mass and BMI were measured. Basic fasting plasma hGH, IGF-I, IGFBP-3, insulin, testosterone and LH as well as prolactin (PRL), FSH and estradiol were assessed by RIA kits. Statistical analysis. Shapiro-Wilk test, Mann-Whitney u-test, Spearman rang correlation coefficient, stepwise multiple regression. RESULTS: Mean serum IGF-I level was the lowest (p<0.005) in group B (172.0+/-54.6 microg/l) and the highest in group C (273.6+/-109.0 microg/l). The mean plasma IGF-I level in group A was similar (NS) (208.3+/-66.5 microg/l) to that found in group B and lower (p<0.02) compared with that in group C. The lowest (p<0.005) serum IGFBP-3 level was found in group B (3.1+/-0.7 microg/l) compared to group C (4.4+/-0.3 microg/l). The mean plasma IGFBP-3 level (3.1+/-1.0 microg/l) in group A was lower than in group C (p<0.005) but identical as in group B. No statistically significant differences between groups were observed in mean hGH levels. Women in group A and C were younger (p<0.001) than those in group B. The lowest mean estradiol level was found in groups A and B. The highest was in group C (p<0.001). Mean plasma LH and FSH levels were higher (p<0.001) in groups A and B vs group C. In group C there were links between IGF-I and age (r=-0.60; p=0.014) The IGF-I/age relation disappeared in the groups A and B (rA=-0.26; rB=0.10; NS). The same regards IGFBP-3/ age link (rA=-0.44, NS; rB=0,31;NS). Estradiol level was related to hGH levels in group C (r=-0.54; p<0.05). In none of groups hGH/IGF-1 as well as IGFBP-3/hGH relations were found. Prolactin accounted for 69% of the variance in IGF-I level in the group B (p=0.003) and for 24% in group A (NS). Testosterone accounted for 88% (p=0.004) of the variance in IGF-I level in group B and IGFBP-3 was responsible for 86% (p=0.038) of the variance in IGF-I level in group C. Again IGFBP-3 was responsible for 47% (p=0.023) in group A and for 49% (p=0.04) in group B of the hGH variance. CONCLUSIONS: 17b-estradiol may be as important contributor to insulin-like growth factor-I (IGF-I) plasma level as age in hypoestrogenic, hypogonadotropic women.     

Effect of testosterone on serum immunoactive inhibin concentrations in intact and hypophysectomized male rats

Intact and hypophysectomized rats were treated with graded doses of testosterone via subcutaneous Silastic implants over a 13-week period. Serum inhibin concentrations fell 50% (P less than 0.001) after 2 weeks of hypophysectomy, remaining suppressed at this level for 13 weeks. The administration of testosterone to hypophysectomized rats (serum testosterone values 2-12 ng/ml; control values 5.5 ng/ml) was without effect on serum inhibin values. In contrast, administration of testosterone to intact animals for 7 weeks resulted in an initial fall (P less than 0.05) in inhibin levels to 50-70% of controls then increasing to reach control levels at higher doses. Serum FSH concentrations were similarly biphasic with increasing dose of testosterone and values for these two hormones were significantly correlated (r = 0.44, P less than 0.01). Segments of seminiferous tubules in culture from rats after various times of hypophysectomy showed a partly suppressed secretion of inhibin. The administration of testosterone did not modify inhibin production although inhibin production was sensitive to FSH. It is concluded that (1) serum inhibin concentrations are partly suppressed after hypophysectomy and testosterone has no effect on serum inhibin values; and (2) the suppression of serum inhibin in intact rats treated with increasing doses of testosterone is attributable to the concomitant fall in serum FSH concentrations.     

Prediction of ovarian response to exogenous gonadotropin stimulation: utilization for collection of primate oocytes for fertilization in vitro

The predictive value of 2 tests for ovarian response to controlled ovarian hyperstimulation in the cynomolgus monkey model was evaluated. The tests utilized were: 1) the cycle Day 3 (Day 1 = onset of menses) FSH value and 2) the acute estradiol (E(2)) response to a GnRH agonists (GnRHa) administered on Day 3. Both tests were performed during the cycle preceding control ovarian hyperstimulation. Subsequently, monkeys (n = 26) were stimulated with Metrodin(T) (Days 2-6, 25IU/d) and Pergonal(T) (Day 7 to hCG administration, 25IU/d). Laparoscopic oocyte retrieval was performed 32 to 34 after hCG administration. Analysis of the data revealed that Day 3 FSH values could not predict whether an animal would respond well to control ovarian hyperstimulation in a subsequent cycle (P = 0.77). However, the E(2) change 24 h post-GnRHa administration was significantly greater for animals responding well to control ovarian hyperstimulation compared with the animals deleted after 6 d of stimulation (P = 0.042). The mean change in E(2) levels in animals taken to aspiration was 97.8 pg/ml compared with only 21.6 pg/ml for the deleted animals. This differential response of E(2) production after GnRHa treatment was used to correctly identify (by discriminant analysis) 78% of the animals subsequently deleted for poor response. Thus, the increase in serum E(2) level after GnRHa, but not the basal FSH level, was found to be predictive of ovarian response to stimulation in the cynomolgus monkey.     

Effect of GnRH antagonists treatment on gonadotrophin secretion, follicular development and inhibin A secretion in goats

The aim of this study was to determine, for goats, the effects of daily doses of GnRH antagonist on ovarian endocrine and follicular function. Ten does were given 45 mg FGA intravaginal sponges and then five were treated with daily injections of 0.5mg of the GnRH antagonist Teverelix for 11 days from 2 days after the day of sponge insertion, while five does acted as controls. Pituitary activity was monitored by measuring plasma FSH and LH daily from 2 days before the first GnRH injection to Day 12. Follicular activity was determined by ultrasonographic monitoring and by assessing plasma inhibin A levels during the same period. In treated does, the FSH levels decreased linearly (0.8 +/- 0.1 ng/ml to 0.5 +/- 0.1 ng/ml, P < 0.01) and remained lower than the mean concentration in control goats (0.8 +/- 0.1 ng/ml, P < 0.005). LH levels were also lower during the period of antagonist treatment (0.6 +/- 0.2 ng/ml versus 0.4 +/- 0.1 ng/ml, P < 0.0005). During GnRH antagonist treatment, there was a significant decrease in the number of large follicles (> or = 6 mm) from Day 3 of treatment (1.2 +/- 0.6, P < 0.0001), with no large follicles from Day 9. The number of medium follicles (4-5 mm in size) also decrease during the period of treatment (4.2 +/- 0.7 to 1.0 +/- 0.6, P < 0.0001), leading to a significant decrease in inhibin A levels when compared to the control (143.7 +/- 31.3 pg/ml versus 65.2 +/- 19.1 pg/ml, P < 0.00005). In contrast, the number of small follicles (2-3 mm) increased in treated goats from Day 4 of treatment (9.6 +/- 2.9 to 20.2 +/- 6.3, P < 0.005). Such data indicate that GnRH antagonist reduced plasma levels of FSH and LH with suppression of the growth of large dominant ovarian follicles and a two-fold increase in number of smaller follicles. The results confirm that GnRH antagonist treatment can be used in goats to control gonadotrophin secretion and ovarian follicle growth in superovulatory regimes.     

Restoration of endocrine and ovarian function after stopping GnRH antagonist treatment in goats

We have tested if the high number of unfertilized ova and degenerated embryos found in superovulated goats previously treated with GnRH antagonist can be related to a prolongation of gonadotrophin down-regulation and/or alterations in follicular function during the period of administration of the superovulatory treatment, around 4 days after the end of the antagonist treatment. A total of 15 does were treated with intravaginal progestagen sponges and daily injections of 0.5mg of the GnRH antagonist Antarelix for 6 days, while 5 does acted as controls receiving saline. During the antagonist treatment, the mean plasma LH concentration was lower in treated than control goats (0.5 +/- 0.2 versus 0.7 +/- 0.5 ng/ml, P < 0.0005 ); however, the FSH levels remained unaffected (0.8 +/- 0.4 versus 0.8 +/- 0.5 ng/ml). In this period, treated does also showed an increase in the number of small follicles with 2-3 mm in size ( 10.7 +/- 0.7 versus 8.4 +/- 0.6, P < 0.05), and a decrease in both the number of follicles > or =4 mm in size ( 5.0 +/- 0.3 versus 6.8 +/- 0.5, P < 0.005) and the secretion of inhibin A (120.9 +/- 10.7 versus 151.6 +/- 12.6 pg/ml, P < 0.05). After cessation of the antagonist treatment, there was an increase in LH levels in treated goats from the day after the last Antarelix injection (Day 1), so that LH levels were the same as controls on Day 3 (0.6 +/- 0.1 versus 0.6 +/- 0.2 ng/ml). However, there were even greater numbers of small follicles than during the period of antagonist injections (15.4 +/- 0.6 in treated versus 8.9 +/- 0.7 in control, P < 0.0005 ). Moreover, the number of > or =4 mm follicles and the secretion of inhibin A remained lower in treated goats (3.9 +/- 0.3 follicles and 84.4 +/- 7.0 pg/ml versus 5.4 +/- 0.5 follicles, P < 0.05 and 128.9 +/- 14.2 pg/ml, P < 0.05 ). These results indicate that pituitary secretion of gonadotrophins is restored shortly after the end of antagonist treatment, but activity of ovarian follicles is affected.