Background Although animal models of PCOS have been used in many studies, none of them can reproduce both the reproductive and metabolic phenotypes of PCOS. In addition, behavioral parameters have not been evaluated in PCOS animal models. Purpose We tried to produce an improved rat model of PCOS, and the reproductive, metabolic, and behavioral phenotypes of the model rats were evaluated. Methods Female rats were implanted with silicon tubes containing oil‐dissolved dihydrotestosterone (Oil‐DHT) as a new PCOS model. Their phenotypes were compared with those of conventional PCOS model rats (DHT), into which tubes containing crystalline DHT were implanted, and non‐DHT‐treated rats (control). Results Both the Oil‐DHT and DHT rats showed greater body weight gain, food intake, and fat depot weight than the control rats. Furthermore, these groups showed fewer estrous stages and increased numbers of cystic follicles. The DHT rats exhibited lower ovarian and uterine weights than the control rats, whereas no such changes were observed in the Oil‐DHT rats. The Oil‐DHT and DHT rats showed less locomotor activity in the light phase than the control rats. Conclusions Our proposed PCOS model reproduced both the reproductive and metabolic phenotypes of PCOS and may have potential for PCOS research.

Polycystic ovary syndrome (PCOS) is frequently seen in females of reproductive age and is associated with metabolic disorders that are exacerbated by obesity. Although body weight reduction programs via diet and lifestyle changes are recommended for modifying reproductive and metabolic phenotypes, the drop-out rate is high. Thus, an efficacious, safe, and continuable treatment method is needed. Recent studies have shown that oxytocin (OT) reduces body weight gain and food intake, and promotes lipolysis in some mammals, including humans (especially obese individuals), without any adverse effects. In the present study, we evaluated the changes in endogenous OT levels, and the effects of acute and chronic OT administration on body weight changes, food intake, and fat mass using novel dihydrotestosterone-induced PCOS model rats. We found that the serum OT level was lower in PCOS model rats than in control rats, whereas the hypothalamic OT mRNA expression level did not differ between them. Acute intraperitoneal administration of OT during the dark phase reduced the body weight gain and food intake in PCOS model rats, but these effects were not observed in control rats. In contrast, chronic administration of OT decreased the food intake in both the PCOS model rats and control rats. These findings indicate that OT may be a candidate medicine that is efficacious, safe, and continuable for treating obese PCOS patients.

Many transgender men receive testosterone therapy to achieve virilization. The therapy is often mistaken for having a contraceptive effect because it causes amenorrhea. However, some treated patients become pregnant, which is not well known. A 25‐year‐old transgender man who had received testosterone for 3 years had an unplanned pregnancy during discontinuation of treatment. He was unaware of his pregnancy, resumed testosterone, and continued treatment until pregnancy was confirmed. His female child was exposed to androgens during the fetal period; thus, careful, long‐term observation was required. He developed insomnia and depression during the postpartum, and giving birth made it difficult for him to change his family register to male. Transgender men can become pregnant through sexual intercourse with biological men, even during hormone replacement therapy, so correct contraception is necessary to avoid unwanted pregnancies. Transgender sex education is important to increase awareness of this issue among individuals and medical professionals.

Background It is known that metabolic and nutritional disturbances induce reproductive dysfunction in females. The main cause of these alterations is reduced gonadotrophin‐releasing hormone (GnRH) secretion from the hypothalamus, and the underlying mechanisms have gradually been elucidated. Methods The present review summarizes current knowledge about the effects of nutrition/metabolism on reproductive functions, especially focusing on the GnRH regulation system. Main findings Various central and peripheral factors are involved in the regulation of GnRH secretion, and alterations in their activity combine to affect GnRH neurons. Satiety‐related factors, i.e., leptin, insulin, and alpha‐melanocyte‐stimulating hormone, directly and indirectly stimulate GnRH secretion, whereas orexigenic factors, i.e., neuropeptide Y, Agouti‐related protein, orexin, and ghrelin, attenuate GnRH secretion. In addition, kisspeptin, which is a potent positive regulator of GnRH, expression is reduced by metabolic and nutritional disturbances. Conclusion These neuroendocrine systems may be defensive mechanisms, which help organisms to survive adverse conditions by temporarily suppressing reproduction.

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