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.
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.
It has been well established that undernutrition and low energy availability disturb female reproductive functions in humans and many animal species. These reproductive dysfunctions are mainly caused ...by alterations of some hypothalamic factors, and consequent reduction of gonadotrophin-releasing hormone (GnRH) secretion. Evidence from literature suggests that increased activity of orexigenic factors and decreased activity of anorexigenic/satiety-related factors in undernourished conditions attenuate GnRH secretion in an integrated manner. Likewise, the activity of kisspeptin neurons, which is a potent stimulator of GnRH, is also reduced in undernourished conditions. In addition, it has been suggested that gonadotrophin-inhibitory hormone, which has anti-GnRH and gonadotrophic effects, may be involved in reproductive dysfunctions under several kinds of stress conditions. It should be remembered that these alterations, i.e., promotion of feeding behavior and temporary suppression of reproductive functions, are induced to prioritize the survival of individual over that of species, and that improvements in metabolic and nutritional conditions should be considered with the highest priority.
Purpose : It is essential to determine normative data of testicular size and penile length in newborn infants in order to assess the development during the fetal period. In this study, we evaluated ...testicular volumes using ultrasonography and also measured penile lengths in Japanese newborn infants. We also examined the associations of the development of these organs with factors including placental weight and anthropometric data. Methods : One hundred and fifteen full-term male newborn infants were recruited for this study. Testicular size was measured by ultrasonography. Results : Mean testicular volumes were 187.4 mm3 in the right testis and 185.4 mm3 in the left testis, and there was no significant difference between the right and left testicular volumes. Right and left testicular volumes showed positive and significant correlations with body lengths and weights. Testicular volumes in the right and left sides were not significantly associated with penile lengths. In 4 groups according to gestational weeks, testicular volume increased significantly with advance of gestational weeks in the left testis. Conclusion : We determined testicular volumes using ultrasonography in Japanese newborn infants. We believe that the results for newborn infants provide important information for assessment of the development of fetal testicular volume. J. Med. Invest. 69 : 256-260, August, 2022
Oxytocin (OT) affects many behavioral, psychological, and physiological functions, including appetite and body weight regulation. Central and peripheral OT levels are markedly affected by gonadal ...steroids, especially estrogen, and the anorectic effects of estrogen are partially mediated by OT in rodents. In this study, the relationship between the estrogen milieu and serum OT levels was evaluated in women of reproductive age under physiological (
= 9) and supraphysiological estrogenic conditions (
= 7). Consequently, it was found that serum OT levels were increased in physiological (the ovulatory phase) and supraphysiological (on the day of the human chorionic gonadotropin trigger in an ovarian stimulation cycle) estrogenic conditions, and that serum OT levels were positively correlated with serum estradiol levels. On the other hand, serum OT levels were negatively correlated with serum progesterone levels, and there was no correlation between serum and follicular OT levels. These results suggest that OT levels may be positively and negatively regulated by estrogen and progesterone, respectively, in humans. However, the physiological roles of these actions of gonadal steroids on OT remain unclear.
In recent years, the effects of androgens on metabolic and body weight regulation systems and their underlying mechanisms have been gradually revealed in females. In women and experimental animals of ...reproductive age, androgen excess can adversely affect metabolic functioning, appetite, and body weight regulation. In addition, excess androgens can increase the risk of metabolic disorders, such as obesity, insulin resistance, and diabetes. These unfavorable effects of androgens are induced by alterations in the actions of hypothalamic appetite-regulatory factors, reductions in energy expenditure, insulin resistance in skeletal muscle, and β-cell dysfunction. Interestingly, these unfavorable effects of androgens on metabolic and body-weight regulation systems are neither observed nor evident in ovariectomized animals and post-menopausal women, indicating that the adverse effects of androgens might be dependent on the estrogen milieu. Recent findings may provide novel sex- and age-specific strategies for treating metabolic diseases.
This study aimed to evaluate the changes in quadriceps femoris muscle thickness during the pregnancy and postpartum periods and to elucidate the effect of bed rest for threatened preterm labor on ...muscle thickness. In 26 women with normal pregnancy, quadriceps femoris thickness was measured at 11-13, 26, 30, and 35 weeks' gestation, and at 3-5 days and 1 month postpartum using ultrasonography. In 15 pregnant women treated with bed rest for threatened premature labor, quadriceps femoris thickness was measured at 30 and 35 weeks' gestation and postpartum. In women with normal pregnancy, quadriceps femoris thickness increased, peaking at 35 weeks' gestation, followed by a postpartum decrease. In women on bed rest, quadriceps femoris thickness showed no significant change during the pregnancy and postpartum periods, and the muscle was significantly thinner at 35 weeks' gestation than that in women with normal pregnancy. In conclusion, a significant increase in quadriceps femoris muscle thickness during normal pregnancy was found using ultrasonography. Meanwhile, in pregnant women on bed rest treatment, the quadriceps femoris was significantly thinner in the late third trimester than that in normal pregnant women. Prolonged bed rest can affect normal changes in the quadriceps femoris muscle thickness during the pregnancy and postpartum periods.
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
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.
Changes in the activities of some metabolic factors have been suggested to increase the risk of conditions associated with the Developmental Origins of Health and Disease (DOHaD). We examined changes ...in oxytocin (OT), a metabolic factor, and OT receptor (OTR) mRNA levels throughout the developmental period in rats of intrauterine undernutrition. Pregnant rats were divided into two groups: a maternal normal nutrition (mNN) and maternal undernutrition (mUN) group. Serum OT concentrations and hypothalamic mRNA levels of OT and OTR were measured in both offspring at various postnatal stages. Both offspring showed significant increases in serum OT concentrations during the neonatal period, significant reductions around the pubertal period, and significant increases in adulthood. Hypothalamic OT mRNA expression levels gradually increased from the neonatal to pubertal period and decreased in adulthood in both offspring. In the pre-weaning period, hypothalamic OT mRNA expression levels were significantly lower in the mUN offspring than in the mNN offspring. In the mUN offspring, hypothalamic OTR mRNA expression levels transiently increased during the neonatal period, decreased around the pubertal period, and increased again in adulthood, whereas transient changes were not detected in mNN offspring. These changes could affect nutritional and metabolic regulation systems in later life and play a role in the mechanisms underlying DOHaD.
PDF
