Response of serum inhibin B and pro-alphaC levels to gonadotrophic stimulation in normal men before and after steroidal contraceptive treatment

BACKGROUND: Testicular regulation of inhibin B may be influenced by the germ cell complement. METHODS: We examined the effects of gonadotrophin stimulation on serum inhibin B and pro-alphaC in 25 normal men at (i) control (stimulation test 1), (ii) after spermatogenic suppression induced by testosterone plus progestin treatment (stimulation test 2), and (iii) during spermatogenic recovery induced by FSH and/or hCG treatment (stimulation test 3). For each test, subjects received a single injection of 1200 IU FSH or 5000 IU hCG or both. RESULTS: Inhibin B and pro-alphaC fell with spermatogenic suppression (75 and 51% of pre-treatment baseline respectively, P < 0.05). Inhibin B response to FSH (130-144%) was similar in controls and after germ cell suppression. Pro-alphaC response after germ cell suppression compared with control was significantly increased (P < 0.05) with both FSH (210-229% versus 140-185%) and hCG (254-261% versus 145%). All treatments partially restored spermatogenesis with no clear relationship apparent between inhibin B and sperm count. CONCLUSIONS: We conclude that: (i) serum inhibin B and pro-alphaC are only partially gonadotrophin dependent, (ii) spermatogenic suppression does not modify inhibin B response to FSH but enhances pro-alphaC response to both FSH and hCG, and (iii) inhibin B is a poor marker of spermatogenesis in this model of gonadotrophic manipulation in normal men.     

Basal and day 12 inhibin concentrations in the prediction of ovarian response to gonadotrophins in women with PCOS

BACKGROUND: In this study, we aimed to investigate whether basal and day 12 serum total inhibin concentrations in women with polycystic ovarian syndrome (PCOS) were of predictive value for the estimation of the ovarian response to gonadotrophins. METHODS: Ovulation induction with a very low dose gonadotrophin protocol, starting with 37.5 IU/day, was performed for 40 cycles on 35 patients with PCOS. Day 3 (basal) serum total inhibin, FSH and oestradiol concentrations; day 12 dominant follicle diameter, inhibin and oestradiol concentrations and midluteal serum progesterone concentrations were measured during the 40 cycles. The correlations between basal and day 12 inhibin concentrations and some critical ovulation monitoring parameters were investigated. RESULTS: Ovulation was obtained in 14 out of 40 cycles: 21% of cycles with basal inhibin <1.0 IU/ml; 33.3% of cycles with basal inhibin between 1.0-1.9 IU/ml; and 83.3% of those with inhibin concentrations > or =2 IU/ml were ovulatory (P < 0.05). Ovulation was achieved in 91.6% of the cycles with a day 12 inhibin concentration > or =4 IU/ml. CONCLUSIONS: Basal inhibin concentrations may determine poor and good responders to ovulation induction with very low dose gonadotrophin protocol in patients with PCOS. The day 12 inhibin concentration was found to be a more sensitive parameter than the oestradiol concentration in the prediction of follicular maturation.     

Dehydroepiandrosterone supplementation augments ovarian stimulation in poor responders: a case series

In patients with poor response to ovarian stimulation with gonadotrophins, growth hormone (GH) is sometimes used to increase paracrine insulin-like growth factor-1 (IGF-1) effect. We postulated that dehydroepiandrosterone (DHEA) administration to poor responders would augment gonado-trophin effect via a similar mechanism. Baseline ovarian stimulation response to a cycle with DHEA in five healthy non-smoking women <41 years old was compared with day 3 FSH <20 mIU/ml. All had documented poor response to vigorous gonadotrophin administration. After day 2 ultrasounds, DHEA-sulphate (DHEA-S), FSH, human chorionic gonadotrophin (HCG), and testosterone were measured, and the women were given 80 mg/day of oral micronized DHEA for 2 months. While still on DHEA, they underwent ovarian stimulation with FSH given i.m. twice a day, and HCG (10 000 IU) at follicular maturity, followed by intrauterine insemination. Cycle parameters assessed were peak oestradiol, and peak oestradiol/ampoule. The DHEA/ovarian stimulation cycles occurred between 4 and 24 months after the control cycles. After 2 months DHEA treatment, DHEA-S increased to 544 +/- 55 microg/dl, and testosterone increased to 67.3 +/- 6.1 ng/dl. All five subjects (six cycles; one subject had two DHEA cycles) had increased responsiveness; peak oestradiol concentrations increased from 266.3 +/- 69.4 pg/ml to 939.8 +/- 418.9 pg/ml. The oestradiol/ampoule ratio increased in all six cycles, by a mean of 2.94 +/- 0.50 fold (P = 0.012). One of the cycles resulted in a delivered twin pregnancy. In this small series, DHEA improved response to ovarian stimulation even after controlling for gonadotrophin dose. Supplemental DHEA treatment during ovarian stimulation may represent a novel way to maximize ovarian response.     

Inhibin and activin secretion during murine preantral follicle culture and following HCG stimulation.

BACKGROUND: Isolation and culture to antral stage of mouse preantral follicles provides an ideal system for investigating the endocrinology of follicular development to maturity. METHODS: The release of inhibin A, inhibin B, pro-alphaC and activin A was measured at specific time-points throughout an in-vitro culture period of 8 days. At the end of culture, follicles were induced to ovulate in vitro by the addition of HCG and the resulting hormone secretion studied both at 20 h and at 6 h intervals. RESULTS: During the preovulatory culture period, the concentrations of inhibin A, B, pro-alphaC and activin A increased significantly. Compared with control, there was a significant decline at 24 h in the concentrations of inhibin A [P < 0.001; 216 +/- 47 versus 823 +/- 110 arbitrary mouse units (amu)/ml], inhibin B (P < 0.01; 131 +/- 23 versus 361 +/- 45 amu/ml) and pro-alphaC (P < 0.001; 14 +/- 5 versus 1198 +/- 212 pg/ml). In contrast, there was a significant increase in the concentration of activin A (P < 0.001; 1.32 +/- 0.04 versus 0.34 +/- 0.03 ng/ml). CONCLUSIONS: These data provide clear evidence of a profound change in the relative secretion rates of inhibin and activin relative to ovulation and suggest that the principal role of activin A may be at time of ovulation rather than during follicular development.     

Main inhibitor of follicle stimulating hormone in the luteal-follicular transition: inhibin A, oestradiol, or inhibin B?

The roles of oestradiol, inhibin A and inhibin B in the luteal-follicular transition were assessed by means of specific assays. Six premenopausal women were studied during a control and then a cycle treated with percutaneous oestradiol 0.1 mg/day from day 10 after the luteinizing hormone (LH) surge until day 4 of the following cycle. Inhibin A concentrations decreased similarly in control and treated cycles from day -5 to day 2, then increased in control cycle to 23.3 +/- 3.4 pg/ml on day 10 (mean +/- SEM). They remained low until day 5 in treated cycles and were lower than controls on day 10 (P < 0.01). Follicle stimulating hormone (FSH) concentrations increased on day 1 in controls and on day 5 in treated cycles when oestradiol concentration fell abruptly. Inhibin B concentrations remained low until day 1 in controls and day 4 in treated cycles. In both, inhibin B concentrations increased 1 day after FSH, peaking at 160 pg/ml. FSH concentrations began to plateau when inhibin B concentrations were >100 pg/ml and oestradiol concentrations below 200 pmol/l. These data suggest that inhibin A is not responsible for FSH suppression in the luteal phase and that the negative control of FSH shifts from oestradiol in the luteal phase to inhibin B in the mid-follicular phase.     

Pharmacodynamics and pharmacokinetics after repeated subcutaneous administration of three gonadotrophin preparations

Recently, several new urinary gonadotrophin preparations have been developed, containing less luteinizing hormone (LH) activity than human menopausal gonadotrophin. Normegon is a gonadotrophin preparation with a follicle stimulating hormone (FSH)/LH ratio of 3:1; Follegon and Metrodin-HP are purified FSH preparations. The aim of the present randomized study was to compare pharmaco-dynamics, -kinetics and local tolerance of these preparations after repeated s.c. administration. Thirty-six healthy female subjects were treated with Lyndiol contraceptive pills for 5 weeks to suppress endogenous gonadotrophin concentrations. After 3 weeks of Lyndiol treatment, 150 IU of Normegon, Follegon or Metrodin HP were administered once daily, s.c. for 7 days. Blood samples were collected once daily during the fourth and fifth weeks of the study and assayed for FSH and oestradiol. After the last gonadotrophin injection, blood samples were collected more frequently to determine pharmacokinetic parameters of FSH. During the fourth and fifth study weeks, daily ultrasound measurements of follicular growth were performed. Endogenous FSH and LH values were extremely suppressed during Lyndiol treatment. Serum FSH values showed similar patterns in the three groups. The maximum FSH concentration was reached 9-11 h post- injection, the terminal half-life was 43-47 h. The preparations were bioequivalent with respect to FSH immunoreactivity. The number of follicles tended to be larger after Normegon than after Follegon and Metrodin HP treatment, though this was not statistically significant. Serum oestradiol concentrations were significantly higher after Normegon treatment. In general, s.c injections were well tolerated. In conclusion, the three preparations were bioequivalent with respect to FSH immunoreactivity. Nevertheless, the biological activity of Normegon tended to be higher than that of Follegon and Metrodin HP in Lyndiol- suppressed women.      

Recombinant human FSH versus highly purified urinary FSH: a randomized study in intrauterine insemination with husbands' spermatozoa

A randomized trial was carried out comparing recombinant FSH (rFSH) and highly purified urinary FSH (uFSH) in intrauterine insemination (IUI) with husbands' spermatozoa. A total of 45 women received rFSH (139 cycles), while 46 women received uFSH (155 cycles). The starting dose was 150 IU/day s.c., beginning on the second day, and on days 6-7 the dose was adjusted according to ovarian response, assessed by vaginal ultrasound and plasma oestradiol concentration. The pregnancy rate according to the intention to treat was 57.8% in rFSH versus 52.2% in uFSH, the corrected pregnancy rates 56.8% and 52.2%, and the cumulative pregnancy rates 69.6% and 61.0%, but the differences were not statistically significant. The per cycle pregnancy rate was 18.12% in rFSH and 15.48% in u-FSH, also not statistically significant. In the rFSH group, the consumption of FSH ampoules per cycle was significantly lower (19.20 +/- 7.02 versus 23. 80 +/- 10.78; P < 0.0001). The ratio of oestradiol/FSH ampoules was significantly higher in rFSH (56.45 +/- 31.26 versus 46.41 +/- 29. 25; P < 0.001). These data indicate that, in IUI cycles, rFSH has a higher potency than uFSH.     

GnRH antagonist-induced inhibition of the premature LH surge increases pregnancy rates in IUI-stimulated cycles. A prospective randomized trial

BACKGROUND: Our prospective randomized controlled trial was designed to assess whether the use of GnRH antagonists can improve the success rate of controlled ovarian stimulation (COS)/intrauterine insemination (IUI) treatments, via inhibition of the premature LH rise. METHODS: A total of 104 patients were randomly divided, using a randomization list, into two groups: in group A (n = 52), recombinant FSH (rFSH) was given with GnRH antagonist Cetrorelix, and in group B (n = 52), the patients received rFSH alone in a manner similar to that of group A. The primary outcome measure was clinical pregnancy rate per couple. RESULTS: The pregnancy rate per patient was 53.8% in group A and 30.8% in group B (P = 0.017). The rate of premature LH surge was 7% in group A and 35% in group B (P < 0.0001). A premature luteinization was observed in two cycles of 144 in group A (1.4%) and in 16 cycles of 154 in group B (10.4%) (P = 0.001). The mean values of LH and progesterone were significantly lower in patients receiving GnRH antagonist than in those who did not (3.3 +/- 3.3 mIU/ml in group A versus 9.9 +/- 7.9 mIU/ml in group B, P < 0.0001, for LH; 1.3 +/- 1.1 ng/ml versus 2.1 +/- 1.9 ng/ml for group A and B, respectively, P < 0.0001, for progesterone). CONCLUSION: The use of GnRH antagonist in COS/IUI cycles improves pregnancy rate, preventing the premature LH rise and luteinization.     

Inhibin A and inhibin B reflect ovarian function in assisted reproduction but are less useful at predicting outcome

To test the hypothesis that dimeric inhibin A and/or inhibin B concentrations represent improved markers of in-vitro fertilization (IVF) outcome over follicle stimulating hormone (FSH), 78 women who achieved pregnancy within three assisted reproduction treatment cycles were matched to 78 women who underwent at least three assisted reproductive treatment cycles and failed to achieve pregnancy. Baseline serum inhibin B and FSH were obtained between days 1 and 4 in a cycle prior to ovarian stimulation, and inhibin A and B were measured immediately before the ovulatory stimulus and in follicular fluid from the lead follicle. Comparing pregnant and non-pregnant subjects at baseline, younger age (34.0 +/- 0.5 versus 36.0 +/- 0.5 years; P < 0.003) and a combination of FSH lower than the median value (11.2 IU/l) and inhibin B higher than the median value (76.5 pg/ml) were associated with pregnancy (P < 0.03), but FSH (11.7 +/- 0.5 versus 12.9 +/- 0.9 IU/ml) and inhibin B (89.0 +/- 10.2 versus 79.7 +/- 7.7 pg/ml) were not independently associated. At the time of the ovulatory stimulus, serum inhibin A (52.8 +/- 3.8 versus 40.0 +/- 2.7 IU/ml; P < 0.004), inhibin B (1623.8 +/- 165.1 versus 859.2 +/- 94.8 pg/ml; P < 0.0009) and the number of oocytes retrieved (14.6 +/- 0.8 versus 10.1 +/- 0.6; P < 0.0001) were predictive of pregnancy when controlled for age. Inhibin A was correlated with the number of embryos (r = 0.4; P < 0.0001). However, neither inhibin A nor inhibin B provided additional information in predicting successful outcome over age and number of oocytes. We conclude that: (i) in patients undergoing assisted reproductive technology, age and number of oocytes retrieved are the strongest predictors of success; (ii) of the parameters available prior to cycle initiation, a combination of lower FSH and higher inhibin B was associated with a greater chance for a successful outcome but an absolute cut-off could not be defined; and (iii) during ovarian stimulation, higher concentrations of inhibin A and inhibin B in serum are associated with successful IVF and mark ovarian reserve as a measure of oocyte number and quality.     

Recombinant follicle stimulating hormone is effective in poor responders to highly purified follicle stimulating hormone

Ovarian stimulation in cases of poor ovarian responsiveness is an important challenge in in-vitro fertilization (IVF) programmes. Despite improvements in oocyte number and quality, an ideal ovarian stimulation strategy has yet to be defined. Here, the results of ovarian stimulation with recombinant follicle stimulating hormone (rFSH) in 28 poor responders to highly purified FSH (FSH-HP) with high basal concentrations of FSH are reported. The protocols used on the FSH-HP and rFSH cycles were identical with the sole exception of the FSH preparation: triptorelin 0.1 mg/day (gonadotrophin-releasing hormone, GnRH-agonist short protocol) and the starting FSH dose of 300 IU/day were administered from day 2 of the menstrual cycle. Ovarian outcome was classified as 'normal', 'intermediate' and 'poor', depending on the number of mature oocytes retrieved and the peak serum oestradiol concentration. Nine of the 28 subjects had an intermediate ovarian response to re-stimulation with rFSH. In the 26 patients who received human chorionic gonadotrophin on both cycles, re-stimulation resulted in a significant increase (P < 0.05) in the mean number of mature oocytes (2.4 +/- 1.4 versus 1.7 +/- 0.8), mean peak oestradiol concentration (606 +/- 252 versus 443 +/- 32 pg/ml) and fertilization rate (73.0 versus 53.3%). Four pregnancies were achieved. It is concluded that rFSH in a GnRH-agonist short protocol improves the ovarian outcome in poor responders to FSH-HP with high basal concentrations of FSH.     

Rescue of IVF cycles by HMG in pituitary down-regulated normogonadotrophic young women characterized by a poor initial response to recombinant FSH

BACKGROUND: The aim of this study was to investigate the effects of adding human menopausal gonadotrophin (HMG) during controlled ovarian stimulation in normoovulatory normogonadotrophic patients showing an initial suboptimal response to a standardized long protocol therapy with recombinant FSH (rFSH) (300 IU/day). METHODS: A total of 43 such patients were randomized in two groups. In Group A, 150 IU rFSH was substituted by 150 IU HMG after day 8 of stimulation. The stimulation protocol of Group B involved a simple increase of the daily rFSH dose to 375 IU after day 8. A total of 40 BMI and age matched patients with an optimal ovarian response formed the control group (Group C). RESULTS: The mean Group A serum concentration of oestradiol on the day of HCG administration and average number of oocytes retrieved were significantly higher than Group B (P < 0.001) and equivalent to Group C. A total of 10 pregnancies (50%) in Group A, 8 (34.8%) in Group B and 19 (47.5%) in the control group were achieved. CONCLUSIONS: The data suggest that LH supplementation improves the ovarian outcome in patients characterized by an inadequate initial response to rFSH therapy in a long protocol.     

Simultaneous evaluation of basal FSH and oestradiol response to GnRH analogue (F-G-test) allows effective drug regimen selection for IVF

To determine whether preliminary assessment of ovarian reserve by simultaneous evaluation of basal follicle-stimulating hormone (FSH) and oestradiol response to gonadotrophin releasing hormone (GnRH) analogue (F-G-test) can be used to tailor individually the drug regimen for ovarian stimulation, the in-vitro fertilization (IVF) results of 238 patients were retrospectively analysed. Sixty-two women with abnormal response to the test (DeltaE2 <180 pmol/l and/or FSH >9.5 mIU/ml) had commenced buserelin nasal spray in the mid-luteal phase and discontinued it on cycle day 1. Ovarian stimulation was started on cycle day 3 with 375 IU/day of gonadotrophin. Fifty-three patients completed the treatment cycle (group A). A total of 176 women with normal response to the test (DeltaE2 >180 pmol/l and FSH <9.5 mIU/ml) had continued the GnRH analogue throughout the stimulation cycle and a starting dose of 225 IU/day of gonadotrophin was used from cycle day 3. A total of 158 patients completed the treatment cycle (group B). Group A had significantly higher age (34.9 +/- 4.2 versus 33.2 +/- 4.2) (P < 0.05) and basal FSH (9.2 +/- 3.8 versus 7.0 +/- 2.2) (P < 0.05) and required a higher total dose of gonadotrophin. The numbers of oocytes retrieved and embryos transferred were significantly lower. However, fertilization, clinical pregnancies, and implantation rates were similar in both groups. It was concluded that simultaneous evaluation of basal FSH and oestradiol response to GnRH analogue can be useful in identifying subcategories of women with reduced ovarian reserve who may benefit from reduced GnRH analogue administration and a higher starting dose of gonadotrophin.     

Elevated FSH concentrations in imminent ovarian failure are associated with higher FSH and LH pulse amplitude and response to GnRH

Imminent ovarian failure (IOF) in women is characterized by regular menstrual cycles and elevated early follicular phase FSH. This study explored underlying neuroendocrine causes of elevated FSH concentrations on day 3 of the menstrual cycle. The characteristics of episodic secretion of FSH and LH, the pituitary response to gonadotrophin-releasing hormone (GnRH), plasma oestradiol, and dimeric inhibin A and inhibin B on day 3 were compared in 13 women with elevated FSH concentrations (>10 IU/l) and 16 controls. FSH amplitudes were higher in the IOF group than in the controls (P < 0. 0001). The FSH pulse frequency did not differ between groups. The FSH response to GnRH was higher in the IOF patients than in the controls (P < 0.0001). Mean LH, LH amplitude and LH response to GnRH were higher in the IOF group, but LH pulse frequency did not differ between the groups. Concentrations of inhibin A and inhibin B were lower in the IOF group, while oestradiol showed no differences. We concluded that in women with IOF, the pituitary is more sensitive to GnRH. This leads to higher FSH and LH pulse amplitudes which underlie the elevated FSH concentrations in the early follicular phase.     

Inhibin A, inhibin B and activin A in the follicular fluid of regularly cycling women

Recent measurements of circulating inhibin A and inhibin B concentrations indicate that inhibin B may play an important role in the selection of dominant follicles. The concentrations of inhibin A, inhibin B and activin A were measured in the follicular fluids of 61 individual follicles (4.8-20 mm in diameter) from 47 regularly cycling women using specific two-site enzyme-linked immunosorbent assays. The microenvironment of each follicle was characterized by measuring follicular fluid androstenedione and oestradiol concentrations. The mean activin A concentrations were < 8 ng/ml for follicles of all sizes (4-17 mm). Inhibin A concentrations were < 1 ng/ml in follicles < 6 mm, and progressively increased to concentrations > 50 ng/ml in follicles > or = 13 mm. Follicles with androstenedione/oestradiol ratios < or = 4 had higher concentrations of inhibin A than follicles with androstenedione/oestradiol ratios > 4. Inhibin B concentrations were higher than inhibin A concentrations in all follicles, increasing from 19.2 +/- 8.3 ng/ml in 4 mm follicles to 409 +/- 9.6 ng/ml in 13 mm follicles and then declining to 275 +/- 47 ng/ml in 17 mm follicles. These results support the hypothesis that inhibin B may play a more important paracrine role in developing follicles and a greater regulatory role with respect to follicle stimulating hormone (FSH) secretion than inhibin A.      

Use of cetrorelix in combination with clomiphene citrate and gonadotrophins: a suitable approach to 'friendly IVF'?

BACKGROUND: With the recently introduced GnRH antagonists, soft stimulation protocols on the basis of clomiphene pretreatment should be possible as the pituitary remains fully sensitive at the beginning of the cycle. METHODS: A prospective trial was carried out on 107 patients undergoing IVF treatment using the multiple dose GnRH antagonist protocol (cetrorelix), clomiphene citrate, and either HMG (n = 54) or recombinant FSH (rFSH) (n = 53). Different stimulation protocols were used to find the most appropriate one for clinical application. RESULTS: Both treatment groups, HMG and rFSH, yielded comparable results concerning gonadotrophin dose, stimulation days and pregnancy rate. A mean number of 6.34 +/- 4.4 metaphase II oocytes was retrieved and a mean number of 2.45 +/- 0.65 embryos was transferred. However, the overall rate of premature LH surges was 21.5% (defined as measurement of LH >10 IU/l and progesterone >1 ng/ml) which is unacceptable for clinical practice. CONCLUSIONS: Increasing the daily cetrorelix dose from 0.25 to 0.5 mg might decrease the number of premature LH surges. Soft stimulation protocols with clomiphene should be used cautiously.     

Dynamic assays of inhibin B and oestradiol following buserelin acetate administration as predictors of ovarian response in IVF

The study was designed to examine whether dynamic measurements of inhibin B and oestradiol following single administration of buserelin acetate were correlated with the ovarian response to stimulation in IVF. A total of 37 patients undergoing IVF treatment was studied when the long protocol was started in the early follicular phase. Blood samples were taken twice: on day 2 of the menstrual cycle, before the first s.c. administration of buserelin acetate 0.5 mg and on day 3, 24 h later. Inhibin B and oestradiol concentrations were compared with the ovarian response to stimulation. The ovarian response was defined in two ways: 'number of oocytes/total recombinant (r) follicle stimulating hormone (FSH) dose'; and 'square-root (number of follicles/total rFSH dose)'. The following measurements were highly correlated with the ovarian response to stimulation: increase in oestradiol (day 3-day 2 oestradiol concentration) [correlation coefficient (r) = 0.68, P: < 0.0001] and sum of inhibin B (day 2 + day 3 inhibin B concentrations) (r = 0.6, P: < 0.0001). Age and basal concentrations of FSH and inhibin B were inferior to the above measurements in terms of correlation with the ovarian response. In conclusion, dynamic measurements of inhibin B and oestradiol following single administration of buserelin acetate were highly correlated with the ovarian response to stimulation for IVF treatment.     

A randomized single-blind controlled trial of letrozole as a low-cost IVF protocol in women with poor ovarian response: a preliminary report

BACKGROUND: Use of letrozole, a selective inhibitor of aromatase, reduces the gonadotrophin dose required to induce follicular maturation. We evaluated whether incorporation of letrozole could be an effective low-cost IVF protocol for poor responders. METHODS: A randomized, controlled, single-blind trial was conducted in the Assisted Reproduction Unit, Institute of Reproductive Medicine, Kolkata, India. Thirty-eight women with a history of poor ovarian response to gonadotrophins were recruited. Thirteen women (Let-FSH group) received letrozole 2.5 mg daily from day 3-7, and recombinant FSH (rFSH) 75 IU/day on days 3 and 8; and 25 women (GnRH-ag-FSH group) underwent long GnRH agonist protocol and stimulated with rFSH (300-450 IU/day). Ovulation was triggered by 10,000 IU of HCG followed by IVF-embryo transfer. The main outcome measures were total dose of rFSH (IU/cycle), terminal estradiol (E2) (pg/ml), numbers of follicles, oocytes retrieved and transferable embryo, endometrial thickness (mm), and pregnancy rate. RESULTS: Compared with the GnRH-ag-FSH group (2865 +/- 228 IU), the Let-FSH group (150 +/- 0 IU) received a significantly (P < 0.001) lower total dose of FSH. Except for terminal E2, which was significantly higher (P < 0.001) in the GnRH-ag-FSH group (380 +/- 46 pg/ml) than the Let-FSH group (227 +/- 45 pg/ml), the treatment outcomes in all other respects, including pregnancy rate, were statistically comparable. CONCLUSIONS: Adjunctive use of letrozole may form an effective means of low-cost IVF protocol in poorly responding women.     

Treatment with the gonadotrophin-releasing hormone antagonist ganirelix in women undergoing ovarian stimulation with recombinant follicle stimulating hormone is effective, safe and convenient: results of a controlled, randomized, multicentre trial. The European Orgalutran Study Group

A multicentre, open-label, randomized study of the gonadotrophin-releasing hormone (GnRH) antagonist ganirelix (Orgalutran((R))/Antagon((TM))) was performed in women undergoing ovarian stimulation with recombinant FSH (rFSH: Puregon((R))). The study was designed as a non-inferiority study using a long protocol of buserelin (intranasal) and rFSH as a reference treatment. A total of 730 subjects was randomized in a treatment ratio of 2:1 (ganirelix:buserelin) using an interactive voice response system which stratified for age, type of infertility and planned fertilization procedure [IVF or intracytoplasmic sperm injection (ICSI)]. The median duration of GnRH analogue treatment was 5 days in the ganirelix group and 26 days in the buserelin group, whereas the median total rFSH dose was 1500 IU and 1800 IU respectively. In addition, in the ganirelix group the mean duration of stimulation was 1 day shorter. During ganirelix treatment the incidence of LH rises (LH >/=10 IU/l) was 2.8% versus 1.3% during rFSH stimulation in the buserelin group. On the day of triggering ovulation by human chorionic gonadotrophin (HCG), the mean number of follicles >/=11 mm diameter was 10.7 and 11.8, and the median serum oestradiol concentrations were 1190 pg/ml and 1700 pg/ml in the ganirelix and buserelin groups respectively. The mean number of oocytes per retrieval was 9.1 and 10.4 respectively, whereas the mean number of good quality embryos was 3.3 and 3.5 respectively. The fertilization rate was equal in both groups (62.1%), and the same mean number of embryos (2.2) was replaced. The mean implantation rates were 15.7% and 21.8%, and the ongoing pregnancy rates per attempt were 20.3% and 25.7% in the ganirelix and buserelin groups respectively. Evaluation of all safety data indicated that the ganirelix regimen was safe and well tolerated. The overall incidence of ovarian hyperstimulation syndrome was 2.4% in the ganirelix group and 5.9% in the reference group. The results of this study support a safe, short and convenient treatment regimen of ganirelix, resulting in a good clinical outcome for patients undergoing ovarian stimulation for IVF or ICSI.     

Endocrinology: Subtle progesterone rise after the administration of the gonadotrophin-releasing hormone antagonist Cetrorelix in intracytoplasmic sperm injection cycles

In the present study, subtle serum progesterone rise (1.1 ng/ml)during the late follicular phase is reported, for the firsttime to our knowledge, in patients using a potent gonadotrophin-releasinghormone (GnRR) antagonist, Cetrorelix, in combination with humanmenopausal gonadotrophin (HMG) for ovarian stimulation priorto intracytoplasmic sperm injection (ICSI). In five out of 24patients (20%) serum progesterone levels were1.1 ng/ml. Thecycle characteristics of the patients were similar in both groups.No premature endogenous luteimzing hor mone (LH) surge occurredand the serum LH concentrations were constantly low during thefollicular phase. The l7- oestradiol and follicle stimulatinghormone (FSH) exposure were higher in cycles with prematureluteinization. The greater oestradiol and FSH exposure confirmthat one of the possible factors inducing subtle serum progesteronerise is the increased oestradiol and FSH induced LH receptivityin granulosa cells.     

Inhibin B in men with normal and disturbed spermatogenesis

Inhibin, a dimeric gonadal glycoprotein, inhibits the production and/or secretion of follicle stimulating hormone (FSH). The major species currently recognized are inhibin A (alphabeta A subunit) and inhibin B (alphabeta B subunit). In men, inhibin B seems to be the physiologically important form of inhibin. Therefore we measured serum inhibin B using a new two-site immunoenzymatic assay in 14 men (mean +/- SEM age, 34.5 +/- 0.7 years) with sperm counts >20 x 10(6)/ ml, in 35 men (mean +/- SEM age, 36.4 +/- 1.3 years) with oligozoospermia (sperm count <20 x 10(6)/ml) and in men with azoospermia (three orchidectomized men, three men with Klinefelter's syndrome, 10 men with Kallmann's syndrome). We compared inhibin B concentrations with serum FSH and sperm concentrations. In men with normal sperm concentrations (44.7 +/- 6.4 x 10(6)/ml), the concentration of inhibin was 223 +/- 18 pg/ml and of FSH 5.0 +/- 0.7 IU/l; in patients with low sperm concentrations (3.7 +/- 0.8 x 10(6)/ml), the concentration of inhibin B was 107 +/- 12 pg/ml and of FSH 12.2 +/- 1.5 IU/l. In all patients, except those with hypogonadotrophic hypogonadism, the relationship between inhibin B and FSH concentrations was inverse (r = -0.69, P < 0.0001). In all patients the sperm concentration was positively correlated with inhibin B concentrations (r = 0.70, P < 0.0001) and negatively correlated with FSH concentrations (r = -0.37, P < 0.01). We conclude that inhibin B may be a marker of exocrine testicular function and could offer improved diagnosis and treatment modalities for male infertility.