Usefulness of random-start progestin-primed ovarian stimulation for fertility preservation

Background Progestin-primed ovarian stimulation (PPOS) has been used in infertility cases in recent years, and several reports have stated that it has oocyte collection results similar to those of gonadotropin-releasing hormone antagonist (GnRH-ant) protocol. For emergency fertility preservation, random-start ovarian stimulation is usually recommended. Therefore we compared the clinical outcomes of random-start PPOS with those of conventional random-start GnRH-ant protocols in fertility-preserving cases. Methods We retrospectively examined 86 cycles of oocyte collection, of which 56 were random-start GnRH-ant and 30 were random-start PPOS for fertility preservation at our hospital between January 2016 and April 2021. The primary outcome was the number of mature oocytes per cycle. The secondary outcome was the number of vitrified blastocysts per cycle for embryo freezing cases. Results No significant differences were noted in the number of days of stimulation, total dose of gonadotropin preparation, and the number of mature oocytes and vitrified blastocysts. The number of hospital visits for monitoring was significantly lower in the PPOS group. The start of menstruation before oocyte collection was significantly less in the PPOS group. Conclusions Random-start PPOS and GnRH-ant were similar in oocyte collection results. PPOS can reduce the number of hospital visits, thus reducing patient stress. PPOS at the start of the luteal phase can prevent the start of menstruation during ovarian stimulation.

Co-existing neuropeptide FF and gonadotropin-releasing hormone 3 coordinately modulate male sexual behavior

Animals properly perform sexual behaviors by using multiple sensory cues. However, neural mechanisms integrating multiple sensory cues and regulating motivation for sexual behaviors remain unclear. Here, we focused on peptidergic neurons, terminal nerve gonadotropin-releasing hormone (TN-GnRH) neurons, which receive inputs from various sensory systems and co-express neuropeptide FF (NPFF) in addition to GnRH. Our behavioral analyses using knockout medaka of GnRH (gnrh3) and/or NPFF (npff) demonstrated that some sexual behavioral repertoires were ‘delayed’, not disrupted, in gnrh3 and npff single knockout males, while the double knockout appeared to alleviate the significant defects that were observed in single knockouts. We also found anatomical evidence to show that both neuropeptides modulate the sexual behavior-controlling brain areas. Furthermore, we demonstrated that NPFF activates neurons in the preoptic area via indirect pathway, which is considered to induce the increase in motivation for male sexual behaviors. Considering these results, we propose a novel mechanism by which co-existing peptides of the TN-GnRH neurons, NPFF and GnRH3, coordinately modulate certain neuronal circuit for the control of behavioral motivation. Our results may go a long way toward understanding the functional significance of peptidergic neuromodulation in response to sensory information from the external environments.

Addition of a carboxy terminal tail to the normally tailless gonadotropin-releasing hormone receptor impairs fertility in female mice

Gonadotropin-releasing hormone (GnRH) is the primary neuropeptide controlling reproduction in vertebrates. GnRH stimulates follicle-stimulating hormone (FSH) and luteinizing hormone (LH) synthesis via a G protein-coupled receptor, GnRHR, in the pituitary gland. In mammals, GnRHR lacks a C-terminal cytosolic tail (Ctail) and does not exhibit homologous desensitization. This might be an evolutionary adaptation that enables LH surge generation and ovulation. To test this idea, we fused the chicken GnRHR Ctail to the endogenous murine GnRHR in a transgenic model. The LH surge was blunted, but not blocked in these mice. In contrast, they showed reductions in FSH production, ovarian follicle development, and fertility. Addition of the Ctail altered the nature of agonist-induced calcium signaling required for normal FSH production. The loss of the GnRHR Ctail during mammalian evolution is unlikely to have conferred a selective advantage by enabling the LH surge. The adaptive significance of this specialization remains to be determined.