Serum luteinizing hormone, follicle-stimulating hormone and oestradiol pattern in women undergoing pituitary suppression with different gonadotrophin-releasing hormone analogue protocols for assisted reproduction

Live births from in vitro fertilization-embryo transfer following the administration of gonadotropin-releasing hormone agonist without gonadotropins: Two case reports

BACKGROUND

The prevalence of female infertility between the ages of 25 and 44 is 3.5% to 16.7% in developed countries and 6.9% to 9.3% in developing countries. This means that infertility affects one in six couples and is recognized by the World Health Organization as the fifth most serious global disability. The International Committee for Monitoring Assisted Reproductive Technology reported that the global total of babies born as a result of assisted reproductive technology procedures and other advanced fertility treatments is more than 8 million. Advancements in controlled ovarian hyperstimulation procedures led to crucial accomplishments in human fertility treatments. The European Society for Human Reproduction and Embryology guideline on ovarian stimulation gave us valuable evidence-based recommendations to optimize ovarian stimulation in assisted reproductive technology. Conventional ovarian stimulation protocols for in vitro fertilization (IVF)–embryo transfer are based upon the administration of gonadotropins combined with gonadotropin-releasing hormone (GnRH) analogues, either GnRH agonists (GnRHa) or antagonists. The development of ovarian cysts requires the combination of GnRHa and gonadotropins for controlled ovarian hyperstimulation. However, in rare cases patients may develop an ovarian hyper response after administration of GnRHa alone.

CASE SUMMARY

Here, two case studies were conducted. In the first case, a 33-year-old female diagnosed with polycystic ovary syndrome presented for her first IVF cycle at our reproductive center. Fourteen days after triptorelin acetate was administrated (day 18 of her menstrual cycle), bilateral ovaries presented polycystic manifestations. The patient was given 5000 IU of human chorionic gonadotropin. Twenty-two oocytes were obtained, and eight embryos formed. Two blastospheres were transferred in the frozen-thawed embryo transfer cycle, and the patient was impregnated. In the second case, a 37-year-old woman presented to the reproductive center for her first donor IVF cycle. Fourteen days after GnRHa administration, the transvaginal ultrasound revealed six follicles measuring 17-26 mm in the bilateral ovaries. The patient was given 10000 IU of human chorionic gonadotropin. Three oocytes were obtained, and three embryos formed. Two high-grade embryos were transferred in the frozen-thawed embryo transfer cycle, and the patient was impregnated.

CONCLUSION

These two special cases provide valuable knowledge through our experience. We hypothesize that oocyte retrieval can be an alternative to cycle cancellation in these conditions. Considering the high progesterone level in most cases of this situation, we advocate freezing embryos after oocyte retrieval rather than fresh embryo transfer.

Pharmacokinetics and Bioavailability of the GnRH Analogs in the Form of Solution and Zn2+-Suspension After Single Subcutaneous Injection in Female Rats

BACKGROUND AND OBJECTIVES

Although many synthetic gonadoliberin analogs have been developed, only a few of them, including buserelin, were introduced into clinical practice. Dalarelin, which differs from buserelin by just one aminoacid in the position 6 (D-Ala), is not widely used so far. Gonadotropin-releasing hormone (GnRH) analogs are used to treat many different illnesses and are available in different forms like solution for injection, nasal spray, microspheres, etc. Unfortunately, none of the above drug formulations can release the hormones for 24 h. We assumed that classical suspension could solve this problem.

METHODS

Two sets of experiments were performed. In the first one, buserelin and dalarelin were injected into mature female rats in two forms: suspension, in which the analogs are bounded by Zn²⁺ ions and solution. The pharmacokinetic parameters and bioavailability of the analogs were calculated, based on their concentration in the plasma measured by high-performance liquid chromatography method (HPLC). In the second experiment, the hormones in two different forms were injected into superovulated immature female rats and then the concentration of Luteinizing hormone (LH), Follicle-stimulating hormone (FSH) and 17β-estradiol in the serum was measured by radioimmunological method.

RESULTS

The Extent of Biological Availability (EBA), calculated on the base of AUC_0-∞, showed that in the form of solution buserelin and dalarelin display, respectively, only 13 and 8 % of biological availability of their suspension counterparts. Comparing both analogs, the EBA of dalarelin was half (53 %) that of buserelin delivered in the form of solution and 83 % when they were delivered in the form of suspension. The injection of buserelin or dalarelin, in the form of solution or suspension, into superovulated female rats increased LH, FSH and estradiol concentration in the serum. However, after injection of the analogs in the form of suspension, the high concentration of LH and FSH in the serum persisted longer.

CONCLUSION

Performed studies indicate that GnRH analogs in the form of suspension have higher bioavailability than their solution counterparts. It influences the effects of their action, especially in relation to LH and FSH.

Outcomes from ovarian hyperstimulation following the sole administration of gonadotrophin-releasing hormone agonist in the context of in vitro fertilization: report of two cases and review of the literature

OBJECTIVE

To report the outcomes from two cases of ovarian stimulation following the sole administration of gonadotrophin-releasing hormone agonist (GnRHa) in the context of in vitro fertilization (IVF).

DESIGN

A case study was conducted.

SETTING

National Referral Unit of Reproductive Medicine.

PATIENTS

Two infertile women undergoing IVF participated in the study.

INTERVENTIONS

Controlled ovarian hyperstimulation using a long protocol. GnRHa (Buserelin) was started in the luteal phase, in a dose of 600 µg/day, for 12 days.

MAIN OUTCOME MEASURES

Number of retrieved oocytes, fertilization rate, number of embryos transferred, implantation rate, ongoing pregnancy, and live birth.

RESULTS

Both women underwent egg retrieval and transfer of good quality embryos. One of them conceived and recently gave birth to a healthy full-term baby.

CONCLUSIONS

The ovarian hyperstimulation after the sole administration of GnRHa is a rare condition. Oocyte retrieval may be a reasonable treatment under these circumstances instead of cycle cancellation. As far as it is known, this is the third case reported of a live birth following the sole administration of GnRHa in the context of IVF.

GnRH signaling, the gonadotrope and endocrine control of fertility

Mammalian reproductive cycles are controlled by an intricate interplay between the hypothalamus, pituitary and gonads. Central to the function of this axis is the ability of the pituitary gonadotrope to appropriately respond to stimulation by gonadotropin-releasing hormone (GnRH). This review focuses on the role of cell signaling and in particular, mitogen-activated protein kinase (MAPK) activities regulated by GnRH that are necessary for normal fertility. Recently, new mouse models making use of conditional gene deletion have shed new light on the relationships between GnRH signaling and fertility in both male and female mice. Within the reproductive axis, GnRH signaling is initiated through discrete membrane compartments in which the receptor resides leading to the activation of the extracellular signal-regulated kinases (ERKs 1/2). As defined by gonadotrope-derived cellular models, the ERKs appear to play a central role in the regulation of a cohort of immediate early genes that regulate the expression of late genes that, in part, define the differentiated character of the gonadotrope. Recent data would suggest that in vivo, conditional, pituitary-specific disruption of ERK signaling by GnRH leads to a gender-specific perturbation of fertility. Double ERK knockout in the anterior pituitary leads to female infertility due to LH biosynthesis deficiency and a failure in ovulation. In contrast, male mice are modestly LH deficient; however, this does not have an appreciable impact on fertility.

To add or not to add LH: comments on recent commentaries

Human reproductive evolution, involving a complex interaction of the hypothalamic-pituitary-ovarian axis, the release of pulsatile and threshold concentrations of gonadotrophins and positive and negative feedback systems, has ensured the release of a single viable egg and functioning corpora lutea in the natural menstrual cycle. The use of follicular stimulation regimens to obtain multiple eggs has resulted in a compromise - in terms of the risk of ovarian hyperstimulation, cost, multiple pregnancies, wastage of or the need for cryopreservation of surplus embryos. Even some women with apparently normal menstrual cycles might become 'poor responders' when administered with follicular stimulants, and we still do not know if the incidence of oocyte aneuploidy is artificially raised after stimulation. After the advent of recombinant FSH and LH, the precise roles of these hormones individually needs to be elucidated to understand the physiological requirements for successful ovarian stimulation in each woman undergoing IVF, to maximize her chance and minimise attendant risks. One of the key debates is the role of LH, which in the natural cycle is significant, but may be redundant during ovarian stimulation for IVF. Current outcome indicators are crude when attempting to understand the physiology, and more basic research and randomized, focused clinical trials are needed.