Luteinizing hormone response to gonadotrophin-releasing hormone in normal women undergoing ovulation induction with urinary or recombinant follicle stimulating hormone

Female Reproductive Behavior

Reproductive behavior is the behavior related to the production of offspring and includes all aspects from the establishment of mating systems, courtship, sexual behavior, and parturition to the care of young. In this chapter, I outline the hormonal regulation of the estrous cycle, followed by a description of the neural regulation of female sexual behavior. Ovarian hormones play an important role in the induction of ovulation and behavioral estrus, in which they interact closely with several neurotransmitters and neuropeptides to induce sexual behavior. This chapter discusses the latest research on the role of estrogen, progesterone, serotonin, dopamine, noradrenaline, oxytocin, and GABA in female mating behavior. In addition, the most relevant brain areas, such as the preoptic area and the ventromedial nucleus of the hypothalamus, in which these regulations take place, are discussed.

Standards of Care in infertility in Europe

Evidence-based medicine is the principal approach to medical practice. There are several debatable issues in infertility, which require clarification. Over the past 20 years, reliable methodology has been developed for the management of infertile couples. This includes high quality diagnostic and therapeutic procedures, which are applied in highly specialised infertility centres. The European Board and College of Obstetrics and Gynaecology (EBCOG) has published Standards of Care for Women's Health in Europe, which should be the cornerstone for the clinicians and service providers in the European Union to establish common protocols within their centres. Each infertility treatment should result in the highest possible success rate and all appropriate measures for the patient's safety should be in place. The treatment protocols should minimise risk of complications, such as ovarian hyperstimulation syndrome (OHSS). The current use of GnRH agonists to trigger final follicle maturation has provided the means for avoiding this syndrome. Additionally, multiple pregnancy rates are still high in assisted reproductive technology (ART). These rates should be reduced by the adoption of single embryo transfer during IVF treatment and by the proper monitoring of ovulation induction protocols. EBCOG Standards of Care for infertility and assisted conception treatment derived from the best available evidence should underpin the provision of high quality infertility services in European countries.

Novel aspects of the endocrinology of the menstrual cycle

Ovarian control of gonadotrophin secretion is normally achieved via the feedback mechanisms mediated by oestradiol and progesterone. Evidence has been provided that nonsteroidal substances, such as inhibin A and B, participate in the negative feedback control of FSH secretion. Another nonsteroidal ovarian substance is gonadotrophin surge-attenuating factor (GnSAF), the activity of which is particularly evident in women undergoing ovulation induction. Accumulating evidence has suggested that GnSAF plays a physiological role during the menstrual cycle. In particular, this factor antagonizes the sensitizing effect of oestradiol on the pituitary response to gonadotrophin-releasing hormone during the follicular phase of the cycle. A hypothesis has been developed that, in the late follicular phase, the activity of GnSAF is reduced and this facilitates the sensitizing effect of oestradiol on the pituitary, thus enforcing the massive discharge of gonadotrophins at the midcycle LH surge. The interaction of oestradiol, progesterone and GnSAF on the hypothalamic-pituitary system provides a novel approach to explain the mechanisms which control LH secretion during the normal menstrual cycle. The ovarian control of gonadotrophin secretion during the normal menstrual cycle is achieved via negative and positive feedback mechanisms. The steroids oestradiol and progesterone are the main regulators; however, nonsteroidal substances, such as inhibin A and inhibn B, also participate. Accumulating evidence has demonstrated that another nonsteroidal ovarian substance, gonadotrophin surge-attenuating factor (GnSAF), plays a key role in the control of LH secretion during the follicular phase and at midcycle, providing thus a novel aspect in the ovarian control of gonadotrophin secretion during the human menstrual cycle. The ovarian control of gonadotrophin secretion during the normal menstrual cycle is achieved via negative and positive feedback mechanisms. The steroids oestradiol and progesterone are the main regulators; however, nonsteroidal substances, such as inhibin A and inhibn B, also participate. Accumulating evidence has demonstrated that another nonsteroidal ovarian substance, gonadotrophin surge-attenuating factor (GnSAF), plays a key role in the control of LH secretion during the follicular phase and at midcycle, providing thus a novel aspect in the ovarian control of gonadotrophin secretion during the human menstrual cycle.

Attenuating activity of the ovary on LH response to GnRH during the follicular phase of the cycle

OBJECTIVE

Oestradiol sensitizes the pituitary to GnRH, while gonadotrophin surge attenuating factor (GnSAF) may oppose this action. Using the LH response to GnRH during treatment with FSH as an in vivo bioassay for GnSAF, we tested the hypothesis that the augmented LH response to GnRH in the late follicular phase is related to reduced production of GnSAF from the ovulatory follicle.

DESIGN

Prospective intervention study.

PATIENTS

Ten healthy, normally cycling women.

MEASUREMENTS

The LH response to 10 μg GnRH i.v. (ΔLH) was investigated on days 2 and 3 and on days v (follicle size 16-17 mm) and v + 1 of cycle 1 (control) and cycle 2. On days 2 and v, a single s.c. injection of either normal saline (cycle 1) or 450 IU recombinant FSH (cycle 2) was given after the end of the GnRH experiment.

RESULTS

FSH injection increased both serum oestradiol and inhibin B. In cycle 1, ΔLH remained unchanged from days 2 to 3 but increased significantly from days v to v + 1. In contrast, in cycle 2, ΔLH decreased significantly from days 2 to 3 (P < 0·05) and showed a nonsignificant increase from day v to day v + 1. The percentage difference in ΔLH between cycle 1 and cycle 2 was similar on days 3 (-66·9 ± 17·5%) and v + 1 (-65·2 ± 3·6%).

CONCLUSIONS

These results suggest that during the follicular phase of the menstrual cycle, GnSAF is produced by small antral follicles, while the contribution of the ovulatory follicle is minimal.

A Two-Pathway Mathematical Model of the LH Response to GnRH that Predicts Self-Priming

An acute response of LH to a stimulatory pulse of GnRH is modelled as a result of a pathway (Pathway I) that consists of two compartments including a single (rate limiting) intermediate. In addition, a second pathway (Pathway II) was added, consisting of an intermediate transcription factor and subsequently a synthesised protein. Pathway II had a delayed effect on LH release due to the time taken to produce the intermediate protein. The model included synergism between these two pathways, which yielded an augmented response. The model accounts for a number of observations, including GnRH self-priming and the biphasic pattern of LH response. The same model was used to fit the data of the LH response when gonadotrophs responded to the addition of oxytocin in the response with a shoulder on the profile. Pathway I is able to be conceptualised as the basic Ca(2+)-mediated pathway. Pathway II contains features characteristic of the cAMP-mediated pathway. Thus, we have provided an explanation for details of the nature of the profile of LH secretion and additionally enabled incorporation of cAMP in an integrating model. The study investigated the possibility of two interacting pathways being at the basis of both the shoulder on the LH surges and self-priming, and the model illustrates that this appears to be highly likely.

Ovarian feedback, mechanism of action and possible clinical implications

The secretion of gonadotrophins from the pituitary in women is under ovarian control via negative and positive feedback mechanisms. Steroidal and non-steroidal substances mediate the ovarian effects on the hypothalamic-pituitary system. During the follicular phase of the cycle, estradiol (E(2)) plays a key role, while circulating progesterone (at low concentrations) and inhibin B contribute to the control of LH and FSH secretion respectively. During the luteal phase, both E(2) and progesterone regulate secretion of the two gonadotrophins, while inhibin A plays a role in FSH secretion. The intercycle rise of FSH is related to changes in the levels of the steroidal and non-steroidal substances during the luteal-follicular transition. In terms of the positive feedback mechanism, E(2) is the main component sensitizing the pituitary to GnRH. Activity of a non-steroidal ovarian substance, named gonadotrophin surge-attenuating factor (GnSAF), has been detected after ovarian stimulation. It is hypothesized that GnSAF, by antagonizing the sensitizing effect of E(2) on the pituitary, regulates the amplitude of the endogenous LH surge at midcycle. Disturbances in the feedback mechanisms can occur in various abnormal conditions or after treatment with pharmaceutical compounds that interfere with the production or the action of endogenous hormones.

Luteal hormonal profile of oocyte donors stimulated with a GnRH antagonist compared with natural cycles

The effect of gonadotrophin-releasing hormone (GnRH) antagonist treatment on luteal phase hormonal profile has not yet been fully investigated. Cycle characteristics of 23 fertile donors stimulated with recombinant FSH and the GnRH antagonist, ganirelix 0.25, for IVF and receiving no kind of luteal supplementation were compared with control, natural cycles. Luteal luteinizing hormone (LH) serum concentrations as well area under the curve (AUC) for LH were significantly higher in natural cycles. In addition, luteal phase length was longer in natural cycles compared with donor cycles. Luteinizing hormone values dropped in the luteal phase of the stimulated cycles, with the lowest values being observed in the mid-luteal phase. AUC for progesterone in the luteal phase was significantly higher in the stimulated cycles compared with natural cycles (P < 0.001). Low LH serum concentrations and shortened luteal phase indicate the need for luteal phase supplementation in GnRH antagonist IVF cycles.

Expression of human serum albumin (HSA) mRNA in human granulosa cells: potential correlation of the 95 amino acid long carboxyl terminal of HSA to gonadotrophin surge-attenuating factor

INTRODUCTION

According to previous studies, gonadotrophin surge-attenuating factor (GnSAF), which is assumed to be produced in human granulosa cells, has a homology with the carboxyl terminal of the human serum albumin (HSA) protein. In an attempt to validate these findings, whole or partial expression of the HSA gene was studied by RT-PCR analysis in human granulosa cells from women undergoing IVF treatment.

METHODS

RT-PCR analysis of HSA RNA transcripts in luteinized granulosa cells was done in order to investigate the possible expression of the HSA gene. To ensure the specificity of PCR products, restriction enzyme and sequence analysis were performed. Western blot analysis was carried out to detect the possible expression of the albumin gene in granulosa cells.

RESULTS

RT-PCR analysis and sequencing analysis of cDNA from granulosa cells revealed bands identical with those from the positive control for the amino as well as the carboxyl terminal corresponding to HSA gene at the cytoplasmic level.

CONCLUSION

We have demonstrated that human granulosa cells express the carboxyl and amino terminal part of the HSA gene in levels comparable to those found in human hepatocytes. It is suggested that the coding gene for GnSAF may be a result of an alternative expression of HSA gene.

The role of aromatase inhibitors in ameliorating deleterious effects of ovarian stimulation on outcome of infertility treatment

Clinical utilization of ovulation stimulation to facilitate the ability of a couple to conceive has not only provided a valuable therapeutic approach, but has also yielded extensive information on the physiology of ovarian follicular recruitment, endometrial receptivity and early embryo competency. One of the consequences of the use of fertility enhancing agents for ovarian stimulation has been the creation of a hyperestrogenic state, which may influence each of these parameters. Use of aromatase inhibitors reduces hyperestrogenism inevitably attained during ovarian stimulation. In addition, the adjunct use of aromatase inhibitors during ovarian stimulation reduces amount of gonadotropins required for optimum stimulation. The unique approach of reducing hyperestrogenism, as well as lowering amount of gonadotropins without affecting the number of mature ovarian follicles is an exciting strategy that could result in improvement in the treatment outcome by ameliorating the deleterious effects of the ovarian stimulation on follicular development, endometrial receptivity, as well as oocyte and embryo quality.

Alternate day and daily administration of GnRH antagonist may prevent premature luteinization to a similar extent during FSH treatment

BACKGROUND

This randomized controlled trial was designed to evaluate whether a GnRH antagonist given every other day could prevent premature luteinization in women undergoing IVF/ICSI treatment.

METHODS

A total of 73 women receiving ovulation stimulation IVF cycles with recombinant FSH were allocated randomly on cycle day 7 to GnRH antagonist ganirelix in multiple doses (0.25 mg each), either daily (n = 37 women, group 1) or every other day (n = 36 women, group 2) until the day of HCG administration.

RESULTS

Serum FSH, LH, estradiol and progesterone values showed similar trends in the two groups. During FSH stimulation, 13 (35%) of the women in group 1 had premature LH rises (> or = 10 IU/l) of which eight (22%) were after the start of antagonist administration. In group 2 there were 14 (39%) LH rises during FSH stimulation of which 10 (28%) were after the start of antagonist administration. Luteinization (serum progesterone >2 ng/ml) occurred in only one woman in each group overall (3%). A significantly smaller total dose of the antagonist was used in group 2 than in group 1 (P < 0.001). The study did not have power to evaluate differences in total dose of FSH, number of oocytes recovered and clinical pregnancy rate, all of which appeared similar in the two groups.

CONCLUSIONS

Whether alternate day is as effective as daily administration of ganirelix in preventing premature luteinization should be addressed in a non-inferiority trial powered to evaluate live birth rate.

FSH and LH responses to GnRH after ovariectomy in postmenopausal women

OBJECTIVE

Whether the postmenopausal ovary is still playing a role in the control of gonadotrophin secretion in response to GnRH has not been investigated. The aim of the present study was to test this hypothesis by examining changes in basal and GnRH-induced gonadotrophin secretion in postmenopausal women after bilateral ovariectomy.

DESIGN

The responses of LH and FSH to GnRH [10 microg intravenously (i.v.)] were investigated in postmenopausal women from 2 days before to 8 days after total abdominal hysterectomy plus bilateral ovariectomy.

PATIENTS

Nine postmenopausal women aged 52-67 years and between 5 and 15 years after menopause. In all cases the ovaries were histologically normal.

MEASUREMENTS

Pituitary responses to GnRH were calculated every 12-24 h as the net increases in LH (DeltaLH) and FSH (DeltaFSH) at 30 min above the basal values. Basal values of oestradiol (E2) and testosterone were also measured.

RESULTS

Basal values of FSH showed a significant decrease on postoperative days 2 (P < 0.01) and 8 (P = 0.03) as compared to day 0, while at the same time points after the operation LH values were marginally lower than on day 2 (P = 0.05). Serum E2 values showed a gradual increase up to postoperative day 1 (P = 0.04) and a gradual decline thereafter. Basal testosterone concentrations decreased gradually and significantly after ovariectomy and were significantly lower on day 8 than on day 0 (P < 0.01). DeltaFSH and DeltaLH responses to GnRH did not change significantly with time. A temporary increase at 12 h after the operation was not significant.

CONCLUSIONS

These results demonstrate for the first time that the removal of the ovaries in postmenopausal women does not affect GnRH-induced gonadotrophin secretion in the short term. It is suggested that the postmenopausal ovary is not a dominant regulator of hypothalamic-pituitary interactions.

Modulatory Effect of the Ovary on LH Secretion

Ovarian steroids are important regulators of gonadotropin secretion during the normal menstrual cycle. Estradiol is the predominant factor in the follicular phase, while progesterone plays an important role in the luteal phase. Gonadotropin surge attenuating factor (GnSAF) is a nonsteroidal ovarian substance that attenuates the endogenous LH surge in superovulated women. Attempts to purify GnSAF from various sources have provided several sequences. In human follicular fluid, GnSAF is shown to be the carboxyl terminal fragment of human serum albumin (HSA) and a molecular mass of 12.5 kDa. Preliminary data have shown the expression of the carboxyl terminal fragment of HSA in human granulosa cells. In vivo studies have provided evidence that GnSAF may participate in the control of LH response to GnRH in the context of a mechanism that facilitates the full expression of the midcycle LH surge. Further research is expected to clarify the role of GnSAF in women's physiology.

Effects of progesterone (P) and antiprogestin RU486 on LH and FSH release by incubated pituitaries from rats treated with the SERM LY11701 8-HCl and/or recombinant human FSH

The aim of the present study was to investigate the role of the estrogen (ES) background on the effects of P or its antagonist RU486 on basal and LHRH-stimulated LH and FSH secretion. To do this, pituitaries collected from: intact rats in proestrus; rats injected with the ES antagonist LY11701 8-HCl; rats injected with recombinant-human FSH (r-hFSH) to stimulate ovarian hormonogenesis; and rats injected with both LY11701 8-HCl and r-hFSH were incubated with or without LHRH (10 nM) in the presence of P (100 nM) or RU486 (10 nM). RU486 decreased basal and LHRH-stimulated release of LH and FSH and LHRH self-priming in pituitaries from control rats, while P increased both pituitary responsiveness and LHRH self-priming. These effects were absent in pituitaries from rats treated either with the ES antagonist or r-hFSH, which, in the absence of P or RU486 in the incubation medium, reduced gonadotropin release. Because r-hFSH did not increase E2 serum concentration significantly, the putative FSH-dependent ovarian non-steroidal gonadotropin surge inhibiting factor (GnSIF) might be the hormonal cause of the reduced secretion of LH and FSH. Combined treatment with LY117018-HCl and r-hFSH had additive inhibitory effects on gonadotropin release. These results indicate that ES-inducible P receptor (PR) in the pituitary can be activated in a ligand-independent manner by intracellular messengers giving rise to enhanced basal and LHRH-stimulated gonadotropin secretion. The results also suggested that the r-hFSH-stimulated ovarian bioactive entity GnSIF and RU486 may share a similar mechanism of action involving pituitary PR.

Ovarian regulators of gonadotropin secretion

Great progress in the ovarian mechanisms that control gonadotrophin secretion in women has recently been achieved. Estradiol (E2) is the main component of the ovarian negative effect on basal gonadotropin secretion during the normal menstrual cycle. However, nonsteroidal substances such as inhibins and activins that can affect follicle-stimulating hormone (FSH) secretion in vitro may also participate in the control of FSH secretion in vivo. Recent evidence has shown that the ovaries also produce another nonsteroidal substance, named gonadotropin surge-attenuating factor (GnSAF), that specifically attenuates GnRH-induced LH secretion and the endogenous LH surge in superovulated women. It is possible that during the normal menstrual cycle GnSAF controls the amplitude of the midcycle LH surge by antagonizing the stimulating effect of E2 on the pituitary.

Comparison of two recombinant follicle-stimulating hormone preparations in in-vitro fertilization: a randomized clinical study

A randomized comparison of two recombinant human follicle-stimulating hormone (recFSH) preparations (Gonal-F and Puregon) in ovarian stimulation for in-vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) was carried out at the Infertility Clinic of the Family Federation of Finland. A total of 348 women (aged 22-43 years) suffering from infertility due to miscellaneous causes was recruited. Of these, 344 underwent stimulation using equal starting doses (150 IU/day: Gonal-F n = 164, Puregon n = 158 or 300 IU/day: Gonal-F n = 8, Puregon n = 14) after down-regulation with intranasal buserelin from the mid-luteal phase. Similar clinical pregnancy rates were achieved with both preparations; 33.5% per cycle and 37.4% per embryo transfer (24.5% one-embryo and 75.5% two-embryo transfers, n = 147) with Gonal-F (150 IU/day) and 32.9% per cycle and 36.4% per embryo transfer (30.1% one-embryo and 69.9% two-embryo transfers, n = 145) with Puregon (150 IU/day). The ongoing cumulative pregnancy rates after frozen-thawed embryo transfer were 35.4% with Gonal-F and 37.7% with Puregon. Six cycles were cancelled because of a low response (three in each group). Similar numbers of oocytes were obtained in both groups; 13.0 with 150 IU/day and 6.1 with 300 IU/day Gonal-F, and 12.4 with 150 IU/day and 7.1 with 300 IU/day Puregon. The fertilization and cleavage rates and the incidence of moderate or severe ovarian hyperstimulation syndrome (Gonal-F, 2.0% and Puregon, 0.7%) were also similar. Gonal-F and Puregon were equally and highly effective in stimulation for IVF and ICSI.

Purification of a candidate gonadotrophin surge attenuating factor from human follicular fluid

Gonadotrophin surge attenuating factor (GnSAF) is a new non-steroidal ovarian substance, different from inhibin, which attenuates the pre-ovulatory luteinizing hormone (LH) surge in superovulated women. Human follicular fluid (FF) was used as a source for the isolation of GnSAF, the activity of which was monitored in an in-vitro pituitary bioassay. Primary rat pituitary cells were incubated with test substances for 48 h and subsequently washed and incubated with 0.1 micromol/l gonadotrophin releasing hormone (GnRH) plus test substances for 4 h. GnSAF activity was expressed as the reduction of GnRH-induced LH secretion in the 4 h incubation. GnSAF was purified from 250 ml of FF which was heat-treated at 80 degrees C for 5 min. Heparin-sepharose chromatography, Con-A sepharose chromatography, reversed-phase high-performance liquid chromatography (HPLC) and preparative native gel electrophoresis were used for GnSAF fractionation. Using these purification steps, we have obtained an apparently homogeneous preparation that stains as a single band on sodium dodecyl sulphate (SDS)-polyacrylamide gel electrophoresis. GnSAF has an apparent molecular weight of 12.5 kDa and was identified by amino acid sequence (mass spectrometry) to be the C-terminal fragment of human serum albumin.