Initiation of periovulatory events in gonadotrophin-stimulated macaques with varying doses of recombinant human chorionic gonadotrophin

During in-vitro fertilization (IVF) cycles, a large bolus of human chorionic gonadotrophin (HCG) is used to induce periovulatory events, but the efficacy of lower doses is undefined. Following follicular stimulation in rhesus monkeys, oocyte nuclear maturation, IVF, granulosa cell luteinization and corpus luteum function were compared after injection of 100, 300 or 1000 IU recombinant HCG or 1000 IU urinary HCG. Bioactive HCG rose to peak concentrations within 2 h that were proportional to the dose administered (100 < 300 < 1000 IU, recombinant HCG = urinary HCG). The duration of surge values (>100 ng/ml) was also dose-dependent (0 h, 100 IU; 24 h, 300 IU; >48 h, 1000 IU, recombinant and urinary HCG). While the proportions of oocytes resuming meiosis and undergoing IVF were similar among groups, fewer animals yielded fertilizable oocytes following 100 and 300 IU (five of nine) compared to 1000 IU recombinant and urinary HCG (nine of 10). Peak values of serum progesterone in the luteal phase were similar, but declined 2 days earlier after 100 and 300 IU relative to 1000 IU recombinant and urinary HCG. Thus, 3-10 fold lower doses of HCG elicit low amplitude surges of short duration that induce periovulatory events such as re-initiation of oocyte meiosis and granulosa cell luteinization. However, oocyte fertilization and luteal function may optimally require surges of higher amplitude and longer duration similar to those produced by standard doses of 1000 IU recombinant or urinary HCG.     

Gonadotrophin-releasing hormone agonist dose-dependency of pituitary desensitization during controlled ovarian hyperstimulation in IVF

The aim of this study was to find the minimal effective daily s.c. dose of the gonadotrophin-releasing hormone (GnRH) agonist, triptorelin acetate, that suppresses the GnRH-induced release of luteinizing hormone (LH) at time of human chorionic gonadotrophin (HCG) injection and thereby prevents spontaneous LH surges during in-vitro fertilization (IVF) stimulation cycles. Therefore, a double-blind, prospective and randomized titration study was performed. A total of 48 IVF patients were divided into four groups of 12 patients. Each group received a different dose of triptorelin acetate, namely 5, 15, 50 or 100 microg s.c. daily. Standard ovarian stimulation was carried out using urinary follicle stimulating hormone (FSH) preparations. A 500 microg GnRH test was performed 90 min before the HCG injection in order to measure the degree of pituitary desensitization. Spontaneous LH surges were not detected in any of the groups, although three patients in the 5 microg group had ovulated at the time of ovum retrieval. The pituitary LH response to the GnRH test at time of HCG, expressed as area under the curve (AUC), appeared to be dose-dependent. Thus, a daily s.c. dose of 100 microg triptorelin acetate appears to be too high, since adequate desensitization of the pituitary (i.e. no spontaneous LH surge) can be achieved with doses as low as 15 and 50 microg.     

Effect of luteinizing hormone on the pattern of steroid production by preovulatory follicles of pregnant mare's serum gonadotropin-injected immature rats

Preovulatory follicles were explanted on the day before ovulation from immature rats given a single injection of Pregnant Mare's Serum gonadotropin (PMS) 2 days earlier. The follicles were incubated for 4 h in modified Krebs bicarbonate buffer containing glucose and albumin in absence or presence of ovine luteinizing hormone (NIH-LH-S18; 0.1-10 mug/ml). The accumulation of progresterone, androstenedione and 17beta-estradiol in the medium was determined by radioimmunoassay. As in indicator of LH exposure the meiotic stage of the follicle-enclosed oocyte was determined at recovery by interference contrast microscopy. The first group of follicles were explanted in the morning, before the endogenous gonadotrophin surge. In hormone-free medium the oocytes remained in the dictyate stage, whereas addition of LH induced oocyte maturation. These follicles, when incubated in hormone-free medium, secreted predominantly androstenedione and estradiol and only low amounts of progesterone. In the presence of LH the secretion of all steroids was enhanced. The second group of follicles were explanted in the evening, 2-4 h after the endogenous gonadotrophin surge. After incubation in hormone-free medium the follicle-enclosed oocytes had matured. The steroid secretion by the follicles was different from that of the first group. In hormone-free medium they secreted predominantly progesterone and low amounts of androstenedione and estradiol. Addition of LH to the medium caused further enhancement of progesterone secretion, but had no effect on androstenedione and estradiol secretion. The third group of follicles were explanted in the evening from rats in which the preovulatory gonadotrophin surge had been prevented by Nembutal treatment. Oocyte maturation and steroid secretion did not differ from that found for the first group of follicles explanted in the morning. The results are compatible with the hypothesis that LH, after a transitory stimulation, inhibits androgen and estrogen secretion and stimulates progesterone secretion by the preovulatory ovarian follicle.     

Scheduled administration of a gonadotrophin-releasing hormone antagonist (Cetrorelix) on day 8 of in-vitro fertilization cycles: a pilot study

To assess in a pilot study the ability of a single injection of a GnRH antagonist (Cetrorelix) to prevent premature luteinizing hormone (LH) surges in an in-vitro fertilization (IVF) embryo transfer programme when administered on a fixed day in the late follicular phase, ovarian stimulation was carried out in 11 women with two ampoules of human menopausal gonadotrophin per day beginning on day 2 of the menstrual cycle. A 3 mg dose of Cetrorelix was administered on day 8 of the stimulation cycle. A second injection was administered 72 h later if ovulation was not triggered in the meantime. We did not observe a premature LH surge in any of the cycles studied. The injection of 3 mg Cetrorelix was capable of preventing LH surge in all the patients studied, introducing a very simple treatment protocol. Among the patients who received two injections (n = 3), the day of the first administration was delayed in two subjects due to slow follicular maturation kinetics. Out of 11 patients, 10 had an embryo transfer. Four clinical pregnancies were obtained (40% per embryo transfer), of which 3 are ongoing (30% per embryo transfer). A simple administration protocol for a new GnRH antagonist (Cetrorelix) was able to prevent LH surges in the 11 patients studied.     

The results of an in vitro fertilization program: two regimens of superovulation

Gonadotropin-releasing hormone (GnRH) agonists are increasingly used in ovarian hyperstimulation protocols in in vitro fertilization (IVF) programs. From March 1992 to June 1993, 565 patients attending our Institute underwent superovulation in 1104 IVF program cycles. Of these cycles, 650 were stimulated with clomiphene citrate and gonadotropins (human menopausal gonadotropin/hMG), and 454 with the GnRH agonist buserelin and hMG in a group of patients who had earlier failed to respond or did not conceive after clomiphene citrate/hMG stimulation. The ovarian response was similar in both groups, however, with the use of buserelin more oocytes were recovered -4.9 +/- 3.2 and 3.5 +/- 2.3 oocytes, respectively. The clinical pregnancy rate per transfer in the group of patients superovulated with buserelin/hMG was twice that of the clomiphene citrate/hMG group (21.0% vs. 10.4%). The relatively high pregnancy rate with the buserelin/hMG regimen in the group of 'poor responders' may be connected with GnRH agonist-induced pharmacological hypophysectomy and the sequelae thereof: normalization of some endocrinopathies, absence of an endogenous luteinizing hormone (LH) surge and better endometrium receptivity, oocytes and embryo quality.     

Modulation of the action of gonadotrophin surge-attenuating factor by gonadotrophin-releasing hormone

Gonadotrophin surge-attenuating factor (GnSAF) is a putative non-steroidal ovarian factor which attenuates the luteinizing hormone (LH) surge in superovulated women through the reduction of the pituitary response to gonadotrophin-releasing hormone (GnRH). The mechanism of action of GnSAF on gonadotrophin secretion was further studied by investigating six normally ovulating women in two cycles--a spontaneous and a follicle-stimulating hormone (FSH)-treated cycle. The response of the pituitary to five consecutive pulses of GnRH was investigated in late follicular phase (follicle size 15 mm) of both cycles. GnRH pulses, 10 micrograms each, were injected i.v. every 2 h and LH was measured in blood samples taken before and 30, 60 and 120 min after each pulse. FSH was injected daily at the fixed dose of 225 IU starting on cycle day 2. Peak values of LH increment occurred 30 min after each pulse. However, maximal LH increment occurred in both cycles after the second GnRH dose. In the FSH cycles the response of LH to the first three pulses was significantly attenuated compared with the spontaneous cycles, while the response to the fourth and fifth pulses was similar in the two cycles. In both cycles, LH increment 30 min post GnRH (net increase above the previous value) was similar after the fourth and fifth pulses. Serum concentrations of oestradiol and immunoreactive inhibin, although higher in the FSH cycles, remained stable throughout the GnRH experimental period in both cycles. These results demonstrate that multiple submaximal doses of GnRH can override the attenuating effect of GnSAF on LH secretion.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hormonal profile during the follicular phase in cycles stimulated with a combination of human menopausal gonadotrophin and gonadotrophin-releasing hormone antagonist (Cetrorelix)

A third generation gonadotrophin-releasing hormone antagonist (Cetrorelix) was used during ovarian stimulation in 32 patients undergoing assisted reproduction, in order to prevent the premature luteinizing hormone (LH) surge. In all patients, ovarian stimulation was carried out with two or three ampoules of human menopausal gonadotrophin (HMG), starting on day 2 of the menstrual cycle. In addition, 0.5 mg of Cetrorelix was administered daily from day 6 of HMG treatment until the day of ovulation induction by human chorionic gonadotrophin (HCG). A significant drop in plasma LH concentration was observed within a few hours of the first administration of Cetrorelix (P < 0.005). Moreover, no LH surge was detected at any point in the treatment period in any of the 32 patients. A mean oestradiol concentration of 2111 +/- 935 ng/l was observed on the day of the HCG administration, indicating normal folliculogenesis. Like LH, progesterone concentration also dropped within a few hours of the first administration of Cetrorelix (P < 0.005). A 0.5 mg daily dose of Cetrorelix prevented a premature LH surge in all the 32 patients treated.     

A bolus of recombinant human follicle stimulating hormone at midcycle induces periovulatory events following multiple follicular development in macaques

The efficacy of follicle stimulating hormone (FSH) as an alternative to luteinizing hormone (LH)/human chorionic gonadotrophin (HCG) for the initiation of periovulatory events in primate follicles is unknown. A single bolus of 2500 IU recombinant (r)-hFSH was compared to 1000 IU r-HCG for its ability to promote oocyte nuclear maturation and fertilization, granulosa cell luteinization and corpus luteum function following r-hFSH (60 IU/day) induction of multiple follicular development in rhesus monkeys. Following the r-hFSH bolus, bioactive luteinizing hormone concentrations were <3 ng/ml. Peak concentrations of serum FSH (1455+/-314 mIU/ml; mean+/-SEM) were attained 2-8 h after r-hFSH, and declined by 96 h. Bioactive HCG concentrations peaked between 2-8 h after r-HCG and remained > or = 100 ng/ml for >48 h, while immunoreactive FSH concentrations were at baseline. The proportion of oocytes resuming meiosis and undergoing in-vitro fertilization (IVF) were comparable for r-hFSH (89%; 47+/-19%) and r-HCG (88%; 50+/-17%). In-vitro progesterone production and expression of progesterone receptors in granulosa cells did not differ between groups. Peak concentrations of serum progesterone in the luteal phase were similar, but were lower 6-9 days post-FSH relative to HCG. Thus, a bolus of r-hFSH was equivalent to r-HCG for the reinitiation of oocyte meiosis, fertilization and granulosa cell luteinization, but a midcycle FSH surge did not sustain normal luteal function in primates.     

Characteristics of synaptic responses of motoneurons to ventrolateral funiculus stimulation in vitro]

Twenty 3-6-week-old Merino lambs were given either 3, 1 or 0 treatments of 50 microg oestradiol benzoate and (48 h later) a 1.5 mg Norgestamet implant left in situ for 9 days (3-, 1- and 0CYCLE+G). On Day 7 after the last implant insertion, and on the same day for 0CYCLE+G, each lamb received 400 I.U. pregnant mare serum gonadotrophin and 6 mg follicle-stimulating hormone (FSH). The reproductive tracts were removed for oocyte collection 24 h after FSH. Reproductive tracts were also collected from 16-24-week-old lambs (n = 31) (0CYCLE-G). The number of antral follicles per ovary was similar for the 3-, 1- and 0CYCLE+G treatments. Similar rates of in vitro maturation and monospermic fertilization were obtained for all groups. The proportion of blastocysts per cleaved oocyte was higher for 1CYCLE+G (50.5%) than for 3CYCLE+G (32.9%), 0CYCLE+G (24.3%), and 0CYCLE-G (11.8%) (P < 0.05). Viable fetuses were obtained at Day 93 of pregnancy after transfer of embryos from all treatments. These results indicate that a single treatment with oestrogen and progesterone, prior to gonadotrophin stimulation, will increase the yield and developmental capacity of oocytes from prepubertal sheep.     

Enhanced bradycardia induced by beta-adrenoceptor antagonists in rats pretreated with isoniazid

Recent studies indicate that the midcycle gonadotropin surge in the human occurs without an increase in hypothalamic gonadotropin-releasing hormone (GnRH) pulse frequency. In addition, previous studies employing a GnRH antagonist to provide a semiquantitative estimate of endogenous GnRH secretion suggest that the overall amount of GnRH secreted is decreased at the time of the surge. To investigate the hypothesis that a normal gonadotropin surge can be generated in the human with a decreased amount of GnRH at the midcycle, 7 GnRH-deficient subjects underwent two cycles of a physiologic regimen of intravenous pulsatile GnRH therapy. In the control cycle, 75 ng/kg/bolus of GnRH, a dose known to be sufficient for folliculogenesis, was administered throughout the cycle, using physiological frequencies. In a second cycle, the bolus dose of GnRH was decreased by one-half log order to 25 ng/kg just prior to the luteinizing hormone surge and returned to 75 ng/kg after documented ovulation. All cycles were ovulatory. The peak luteinizing hormone level (77.4 +/- 9.7 vs. 67.5 +/- 17.6 IU/l) did not differ between the control and decreased GnRH cycles. There was no difference in the peak serum estradiol level (475.8 +/- 144.1 vs. 493.2 +/- 93.0 pg/ml), follicular phase length (15.0 +/- 1.3 vs. 14.8 +/- 0.6 days), or progesterone level (22.4 +/- 5.1 vs. 34.8 +/- 5.7 ng/mg) on day 6 of the luteal phase in the control and decreased GnRH cycles, respectively. Three pregnancies were achieved in each of the control and reduced GnRH cycles. We conclude that a decreased overall amount of GnRH generates a normal midcycle gonadotropin surge and has no significant impact on luteal phase adequacy or fertility. These results provide further evidence that a decrease in endogenous hypothalamic GnRH secretion may occur at the midcycle in normal women. This study also provides evidence that the GnRH requirements for normal follicular and luteal phase dynamics may well be greater than those required for generation of a normal midcycle gonadotropin surge and ovulation in women.     

Outcome from consecutive in-vitro fertilization/intracytoplasmic sperm injection attempts in the final group treated with urinary gonadotrophins and the first group treated with recombinant follicle stimulating hormone

In the absence of specific dose equivalency data, the aim of this study was to compare the clinical results during the cross-over from menopausal urinary products (human menopausal gonadotrophin; HMG) to recombinant follicle stimulating hormone (FSH) follitrophin beta (FSHr) in order to determine whether the manufacturer's recommendation for equivalence of ampoule to ampoule (50 IU FSHr:75 IU HMG) would prove clinically correct. A total of 353 consecutive in-vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) treatment cycles was studied between 1st September 1996 and mid-February 1997. This included cycles in the last 191 women receiving HMG and the first 162 taking FSHr. All were down-regulated using a gonadotrophin releasing hormone (GnRH) agonist long protocol method from day 1 of the cycle. Greater efficacy was seen in the HMG group in terms of days of stimulation required, need to increase dosage, cycle discontinuation, number of follicles punctured, the numbers of oocytes retrieved and their quality. The hormonal response to stimulation assessed by oestradiol concentrations on days 5, 8 and day of human chorionic gonadotrophin (HCG) was significantly lower in the FSHr group. The ratio of oestradiol per follicle and per oocyte was significantly lower in the FSHr group. There was a highly significant increase in cost with FSHr therapy. Clinical pregnancy rates were 14% per cycle with FSHr and 20% per cycle with HMG.     

Reducing the dose of gonadotrophin-releasing hormone agonist on starting ovarian stimulation: effect on ovarian response and in-vitro fertilization outcome

The aim of this study was to examine if lowering the dose of gonadotrophin-releasing hormone agonist (GnRHa) on starting ovarian stimulation could be beneficial in in-vitro fertilization (IVF) programmes. A total of 64 normally ovulating patients entering an IVF programme were randomized to receive GnRHa (nafarelin acetate/Synarel) as an intranasal spray commencing in the midluteal phase, either at a dosage of 200 microg three times daily until the day of human chorionic gonadotrophin (HCG) administration, or to be reduced to 200 microg twice daily as ovarian stimulation was initiated. Patients in both groups were below 35 years with a body mass index below 30. All patients received three ampoules of Metrodin HP per day. Blood samples were taken on the day of HCG administration to measure luteinizing hormone (LH), oestradiol, and progesterone. LH and oestradiol were found to be significantly higher in the lower Synarel dose group. Our results show that reducing the GnRHa dose during ovarian stimulation in IVF might be beneficial in terms of significantly more oocytes recovered, and significantly greater number of embryos available for transfer and freezing, with no incidence of premature luteinization.     

Human chorionic gonadotrophin and steroid concentrations in follicular fluid: the relationship to oocyte maturity and fertilization rates in stimulated and natural in-vitro fertilization cycles

The study investigates the relationship of follicular fluid steroids and human chorionic gonadotrophin to oocyte maturity and fertilization rates in stimulated and natural cycles. Oestradiol, progesterone, testosterone and human chorionic gonadotrophin were quantified in 129 samples of follicular fluid and the progesterone:oestradiol ratio calculated. Both stimulated cycles (short and long luteinizing hormone-releasing hormone/human menopausal gonadotrophin regimens) and natural cycles were compared. A total of 60 women were studied, 20 in each group. In the natural cycles, testosterone was significantly lower in follicles with intermediate oocytes (P = 0.015). Both oestradiol and testosterone were significantly lower in stimulated cycles compared to natural cycles (P = 0.032 and P = 0.034 respectively). In the ovarian stimulation cycles, the progesterone:oestradiol ratio was significantly higher when oocytes fertilized (P = 0.052). Moreover, in the stimulated cycles, oestradiol and human chorionic gonadotrophin were singnificantly lower in the short protocol compared to the long protocol. The data demonstrate that the hormonal milieu of the follicle is altered in down-regulated stimulated cycles to varying degrees, depending partially on the type of protocol used. Furthermore, the progesterone:oestradiol ratio, rather than individual hormone concentrations, may be a useful predictor of the fertilizing capacity of the oocytes.     

Corpus luteum function and pregnancy rates with clomiphene citrate therapy: comparison of human chorionic gonadotrophin-induced versus spontaneous ovulation

A total of 508 clomiphene citrate cycles with intra-uterine insemination (IUI) performed in 233 consecutive patients were studied. In 247 cycles insemination was performed 36-38 h after human chorionic gonadotrophin (HCG)-triggered ovulation; in the remaining 261 cycles IUI was performed 18-20 h after urinary luteinizing hormone (LH) kit detection of a spontaneous LH surge. Corpus luteum function, as determined by luteal phase length and mid-luteal progesterone concentrations, together with pregnancy rates were analysed. There was no difference in luteal phase parameters between spontaneous and HCG-triggered cycles when adjusting for patient age. Furthermore, the pregnancy rates did not differ between the HCG and LH kit groups, even after adjusting for patient age and number of motile spermatozoa inseminated. Additionally, the large numbers of cycles analysed provided sufficient power to detect increases in clinical pregnancy rates in spontaneous ovulatory cycles and HCG-induced ovulation of 10.1 and 2.4% respectively, using the customary significance level (alpha-type error) of 0.05. These findings indicate that pregnancy rates and corpus luteum function in carefully monitored clomiphene citrate/IUI cycles do not differ between HCG-triggered and spontaneous ovulatory cycles.     

Insulin stimulation of lactate accumulation in isolated human granulosa-luteal cells: a comparison between normal and polycystic ovaries

Polycystic ovary syndrome (PCOS) is often associated with hyperinsulinaemia and peripheral insulin resistance. Whether the ovary is resistant to insulin is a matter of controversy. The aim was therefore to study the effect of insulin on lactate accumulation, an indicator of glucose metabolism, in granulosa-luteal cells from women with PCOS and from women with normal ovarian function. The cells were obtained from women undergoing clinical in-vitro fertilization-embryo transfer, either from patients with normal ovarian function and tubal or male infertility, or from women with PCOS, with or without tubal factor. The patients were down-regulated with buserelin and stimulated with urofollitrophin and human chorionic gonadotrophin (HCG). Follicle aspiration was performed under ultrasound guidance. Following oocyte recovery the granulosa-luteal cells were isolated, washed and cultured (2-3 x 10(4) viable cells/well) in serum-free Eagle's minimal essential medium for 48 h. After washing, the cells were then cultured in medium containing HCG (0.1-10 IU/ml) or insulin (0.05-0.5 microg/ml) for 24-48 h. Lactate accumulation in the media and cellular protein were analysed. Basal lactate accumulation did not differ in granulosa-luteal cells obtained from normal or PCOS ovaries, and averaged 46 and 49 nmol/g protein/24 h, respectively. A significant stimulation (40-60%) was obtained by HCG in both groups. Insulin caused a dose-dependent increase in lactate in granulosa-luteal cells obtained from normal ovaries (control: 45.5 +/- 6.3; insulin 0.5 microg/ml: 77 +/- 10 nmol/microg protein). Lactate accumulation in granulosa-luteal cells from PCOS ovaries was not altered in the presence of insulin. These results suggest that granulosa-luteal cell glucose metabolism is resistant to insulin in PCOS.     

Cardiac effects of formoterol and salmeterol in patients suffering from COPD with preexisting cardiac arrhythmias and hypoxemia

OBJECTIVE: There are several reports of documented adverse cardiac effects during treatment with beta-agonists. Since one should be aware that this may be a problem in patients with preexisting cardiac disorders, we have conducted a randomized, single-blind, balanced, crossover, placebo-controlled study to assess the cardiac effects of two single doses of formoterol (12 microg and 24 microg) and one single dose of salmeterol (50 microg) in 12 patients suffering from COPD with preexisting cardiac arrhythmias and hypoxemia (PaO2<60 mm Hg). DESIGN: Each patient was evaluated at a screening visit that included spirometry, blood gas analysis, plasma potassium measurement, and 12-lead ECG. In following nonconsecutive days, all patients underwent Holter monitoring 24 h during each of the four treatments. Holter monitoring was started soon before drug administration in the morning. Plasma potassium level was measured before drug inhalation, at 2-h intervals for 6 h, and at 9, 12, and 24 h following administration. None of our patients took rescue medication during the 24-h period. RESULTS: Holter monitoring showed a heart rate higher after formoterol, 24 microg, than after formoterol, 12 microg, and salmeterol, 50 microg, and supraventricular or ventricular premature beats more often after formoterol, 24 microg. Formoterol, 24 microg, significantly reduced plasma potassium level for 9 h when compared with placebo, whereas formoterol, 12 microg, was different after 2 h and salmeterol, 50 microg, from 4 to 6 h. CONCLUSIONS: The results of this study suggest that if a COPD patient is suffering from preexisting cardiac arrhythmias and hypoxemia, long-acting beta-agonists may have adverse effects on the myocardium, although the recommended single dose of salmeterol and formoterol, 12 microg, allows a higher safety margin than formoterol, 24 microg.     

Attitudes about treatment of coronary heart disease among women and men presenting for exercise testing

In recent years, several potent gonadotropin-releasing hormone (GnRH) analogues have become available for female contraception and one of them (buserelin) has been tested in lactating women. However, the possible effects on infants due to the transference of the analogue through breast milk have not been studied. The present work evaluated the effect of oral buserelin on urinary LH secretion in male infants. A total of 19 healthy full-term boys (aged 2-4 months) were included in the study. Infants received orally a single dose of a GnRH agonist mixed with breast milk. Urine samples were collected prior to, and 4-6 and 24 h after treatment for LH measurement. The results disclosed a significant increase in LH urine level in the sample taken 4-6 h after buserelin administration. Twenty-four hours after GnRH agonist ingestion, the LH level returned to baseline level. The present study demonstrated that GnRH analogue administered orally to infants escapes from gastrointestinal inactivation and induces a significant rise in LH levels 4-6 h after treatment.     

Administration of antiserum against ovine follicle-stimulating hormone or ovine luteinizing hormone at pro-poestrus in the rat: effects on follicular development during the oncoming cycle

Cyclic rats received at 13.00 h on the day of pro-oestrus a single i.v. injection of one of the following antiserum preparations: AOLH (raised in rabbits against NIH-LH-S17); AOFSH (raised against NIH-FSH-S9) or pAOFSH (AOFSH preincubated with 195 mug NIH-LH-S16/ml). Rats were killed at day 1, 3 or 5 after injection, and the ovaries prepared for histological study of the antral follicles. After AOLH, ovulation and resumption of meiosis in oocytes in pre-ovulatory follicles were prevented but follicular development during the following cycle appeared undisturbed. After either AOFSH or pAOFSH, blockade of ovulation was never observed but the formation of antral follicles normally occurring between mid-pro-oestrus and mid-oestrus was postponed by about one day. The later development of antral follicles might reflect a supranormal compensatory secretion of endogenous gonadotrophin because the development does not occur in AOFSH- or pAOFSH-treated rats hypophysectomized 24 h after injection and subsequently treated with pregnant mare serum gonadotrophin in dosage approximating the amount of gonadotrophin secreted endogenously during dioestrus. The results imply (1) that the pre-ovulatory surge of LH release is not essential for follicular development during the oncoming cycle whereas (2) a surge of FSH release is required for the formation of the new cohort of antral follicles that is normally seen at the start of a new cycle.     

Follicle stimulating hormone-granulosa cell axis involvement in the antifolliculotrophic effect of low dose mifepristone (RU486)

This study was designed to assess the involvement of follicle stimulating hormone (FSH)-granulosa and luteinizing hormone (LH)-theca axes in the antifolliculotrophic effect of mifepristone. Plasma gonadotrophins, including plasma LH bioactivity and pulsatility, oestradiol, testosterone and inhibin concentrations, and follicular growth were monitored in volunteer women treated with placebo or mifepristone in two consecutive cycles. Mifepristone was given either as a single dose of 5 mg (n = 7) when the leading follicle had reached a diameter between 12 and 14 mm, or as a multiple dose of 5 mg/day for 3 days, beginning when the leading follicle had reached a diameter between 14 and 16 mm (n = 5) or between 6 and 11 mm (n = 5). Following the single dose of mifepristone, follicular growth and the accompanying increase in plasma oestradiol were arrested at 12 and 36 h respectively without changes in gonadotrophin or testosterone serum concentrations. The 3 day regimen arrested follicular growth and oestradiol rise and decreased plasma inhibin concentrations when follicles were larger than 12 mm at the onset of treatment. These results indicate that the antifolliculotrophic action of mifepristone is associated with a selective compromise of the FSH-granulosa axis of dominant follicles that have passed a critical stage of growth.     

Continuing the debate on empty follicle syndrome: can it be associated with normal bioavailability of beta-human chorionic gonadotrophin on the day of oocyte recovery?

This paper describes our experience with four ovarian stimulation in-vitro fertilization (IVF) cycles in which we failed to retrieve oocytes despite normal bioavailability of beta-human chorionic gonadotrophin (beta-HCG) in patients' blood 35 h after HCG administration. In three cases, the oocyte recovery procedure was interrupted, a second dose of HCG was administered and 24 h later mature oocytes were collected from two of the patients. In the first case, the three metaphase II oocytes collected fertilized after intracytoplasmic sperm injection (ICSI) and two cleaved grade three embryos were transferred but pregnancy did not ensue. In the second case, six out of eight metaphase II oocytes fertilized and cleaved following ICSI, leading to transfer of one grade two and two grade three embryos. This resulted in a clinical pregnancy which at the time of this report is ongoing. A similar rescue protocol was used for the third case who had empty follicle syndrome (EFS) in her previous treatment cycle but only cumulus-corona complexes were aspirated. Five additional patients who had EFS before instituting pregnancy diagnostic test screening have had further treatment cycles in which oocytes were collected but pregnancy did not ensue. We conclude that normal bioavailability of beta-HCG on the day of oocyte recovery does not exclude the diagnosis of EFS. EFS does not predict a reduced fertility potential in future cycles, although it may recur due to a biological abnormality in the availability of mature oocytes that are retrievable. In such patients, oocyte donation may offer the chance of achieving a pregnancy.