The influence of psychological stress in early life on sexual maturation and sexual behavior in male and female rats.

Purpose: We studied the influence of psychological stress during the early neonatal period on sexual maturation and sexual behavior in rats.

Methods: Neonatal male and female rats were divided into control (C) and maternal separation (MS) groups (n = 20-24 per group). The pups in the MS groups were placed in isolation cages for 240 minutes/d from postnatal days 2-11.

The reduction in sexual behavior of adult female rats exposed to immune stress in the neonatal period is associated with reduced hypothalamic progesterone receptor expression.

Purpose: We examined the mechanism by which neonatal immune stress reduces the sexual behavior of female rats in adulthood.

Methods: Neonatal female rats were randomly divided into 3 groups: control (n = 11), postnatal day 10 lipopolysaccharide (PND10LPS) (n = 23), and PND25LPS (n = 11) groups, which received intraperitoneal injections of LPS (100 μg/kg) or saline on PND10 and 25. Daily inspections of the vaginal opening (VO) were performed from PND27 to PND37.

The reduction in sexual behavior induced by neonatal immune stress is not related to androgen levels in male rats.

Purpose: It is known that various types of stress in early life increase the incidence of diabetes, myocardial infarctions, and psychiatric disorders in adulthood. We examined the mechanism by which neonatal immune stress reduces sexual behavior in adult male rats.

Methods: Male rats were randomly divided into 3 groups: the control (n = 17), postnatal day 10 lipopolysaccharide (PND10LPS) (n = 31), and PND25LPS (n = 16) groups, which received intraperitoneal injections of LPS (100 μg/kg) or saline (injection volume: ≤0.

Prenatal undernutrition suppresses sexual behavior in female rats.

Infectious, psychological and metabolic stresses in the prenatal and early neonatal period induce long-lasting effects in physiological function and increase the risk of metabolic disorders later in life. We examined the sexual behavior of female rats that were subjected to undernutrition in the prenatal period. Eight pregnant rats were divided into two groups: a maternal normal nutrition group (mNN; n = 4) and a maternal undernutrition group (mUN; n = 4), which received 50% of the daily food intake amount of the mNN group from gestation day 13 to delivery.

Neurokinin B receptor agonist and Dynorphin receptor antagonist stimulated luteinizing hormone secretion in fasted male rodents.

Kisspeptin/neurokinin B (NKB)/dynorphin (Dyn) (KNDy) neuron in hypothalamic arcuate nucleus plays a key role in GnRH/LH pulsatile secretion. We aimed to determine whether stimulation of NKB/neurokinin 3 receptor (NK3R) signaling and inhibition of Dyn/kappa-opioid receptor (KOR) signaling recover LH secretion that is suppressed by acute fasting in male rats. Furthermore, we determined dose dependent effect of NKB/NK3R signaling on serum LH level under acute fasting condition in male mice.

Prenatal undernutrition disrupted the sexual maturation, but not the sexual behavior, in male rats.

Purpose: Exposure to various stressors, including psychological, metabolic, and immune, in the perinatal period induces long-lasting effects in physiological function and increase the risk of metabolic disorders in later life. In the present study, sexual maturation and sexual behavior were assessed in prenatally undernourished mature male rats.

Methods: All the pregnant rats were divided into the maternal normal nutrition (mNN) group and the maternal undernutrition (mUN) group.

Clinical outcome of various metformin treatments for women with polycystic ovary syndrome.

Aim: Polycystic ovary syndrome (PCOS) is an ovulatory disorder and insulin resistance and diabetes are involved in its pathophysiology. Metformin, an anti-diabetic agent, has been reported to be useful to induce ovulation.

Methods: Metformin treatment was classified into four types: (1) clomiphene-metformin combination treatment for clomiphene-resistant patients; (2) clomiphene-metformin combination for clomiphene-sensitive patients; (3) clomiphene-metformin combination for naïve patients; and (4) metformin monotherapy.

The effects of chronic testosterone administration on body weight, food intake, and adipose tissue are changed by estrogen treatment in female rats.

In females, estrogens play pivotal roles in preventing excess body weight (BW) gain. On the other hand, the roles of androgens in female BW, appetite, and energy metabolism have not been fully examined. We hypothesized that androgens' effects on food intake (FI) and BW regulation change according to the estrogens' levels.

Relationship between serum anti-Mullerian hormone and clinical parameters in polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is an ovulatory disorder that affects 6-10% of women of reproductive age. Serum AMH level may be an additional factor, or surrogate of PCOM, in the diagnostic criteria of PCOS. We evaluated the correlations between the serum AMH level and various endocrine and metabolic features in PCOS using the latest fully automated assay.

The effects of prenatal undernutrition and a high-fat postnatal diet on central and peripheral orexigenic and anorexigenic factors in female rats.

Prenatal undernutrition and postnatal overnutrition increase the risk of some peripheral and central metabolic disorders in adulthood. We speculated that disturbances of appetite/metabolic regulatory factors might already have been established in the early stages of life and contribute to obesity later in life. The effects of a high-fat diet on the levels of peripheral and central appetite/metabolic regulatory factors were compared between the offspring of normally nourished dams and those of undernourished dams in the peri-pubertal period.

Kisspeptin mRNA expression is increased in the posterior hypothalamus in the rat model of polycystic ovary syndrome.

Hypersecretion of luteinizing hormone (LH) is a common endocrinological finding of polycystic ovary syndrome (PCOS). This derangement might have a close relationship with hypothalamic kisspeptin expression that is thought to be a key regulator of gonadotropin-releasing hormone (GnRH). We evaluated the relationship between the hypothalamic-pituitary-gonadal axis (HPG axis) and kisspeptin using a rat model of PCOS induced by letrozole.

Developmental changes in the hypothalamic mRNA expression levels of brain-derived neurotrophic factor and serum leptin levels: Their responses to fasting in male and female rats.

The actions and responses of hypothalamic appetite regulatory factors change markedly during the neonatal to pre-pubertal period in order to maintain appropriate metabolic and nutritional conditions. In this study, we examined the developmental changes in the hypothalamic mRNA levels of brain-derived neurotrophic factor (BDNF), which is a potent anorectic factor and the changes in the sensitivity of the hypothalamic expression of this factor to fasting during the neonatal to pre-pubertal period. Under fed conditions, hypothalamic BDNF mRNA expression decreased during development in both male and female rats.

Developmental changes in the hypothalamic mRNA expression levels of PACAP and its receptor PAC1 and their sensitivity to fasting in male and female rats.

The actions and responses of hypothalamic appetite regulatory and factors change markedly during the neonatal to pre-pubertal period. Pituitary adenylate cyclase-activating polypeptide (PACAP) has been found to play pivotal roles in the regulation of metabolic and nutritional status through its specific receptor PAC1. PACAP/PAC1 have anorectic roles, and their functions are regulated by leptin in adulthood.

Effects of chronic testosterone administration on body weight and food intake differ among pre-pubertal, gonadal-intact, and ovariectomized female rats.

In females, estrogens play pivotal roles in preventing excessive body weight gain. On the other hand, the roles of androgen in female appetite and body weight regulation have not been fully studied. In this study, whether the roles of androgen in the regulation of body weight and appetite were different among ages and/or the estrogen milieu in females was evaluated.

The sensitivity of adipose tissue visfatin mRNA expression to lipopolysaccharide-induced endotoxemia is increased by ovariectomy in female rats.

Visfatin plays an important role in inflammatory and metabolic conditions. In this study, the effects of septic stress on the serum, white-adipose-tissue (WAT), and liver visfatin levels of male and female rats were examined. Both gonadally intact (sham) and ovariectomized (OVX) female rats were used in order to evaluate the effects of the gonadal hormonal milieu on visfatin responses.

Effects of chronic DHEA treatment on central and peripheral reproductive parameters, the onset of vaginal opening and the estrous cycle in female rats.

The neonatal and/or prepubertal androgen milieu affects sexual maturation and reproductive function in adulthood. However, the effects of chronic dehydroepiandrosterone (DHEA) treatment on reproductive functions have not been fully elucidated. Therefore, the reproductive phenotypes and parameters of rats that had been subjected to chronic DHEA treatment were evaluated in this study.

The advancement of the onset of vaginal opening in female rats subjected to chronic testosterone treatment occurs independently of hypothalamic Kiss1 and RFRP expression.

Objective: The neonatal and/or prepubertal androgen milieu affects sexual maturation. In rodents, neonatal chronic testosterone treatment, which is used as a model of polycystic ovary syndrome (PCOS), results in the onset of vaginal opening occurring earlier in the pubertal period.

Design: In the present study, the changes in hypothalamic Kiss1 (a gonadotropin-releasing hormone (GnRH)-stimulating factor) and RF-amide related peptide (RFRP; a GnRH inhibitory factor) mRNA expression induced by testosterone treatment were examined in order to clarify whether these factors are involved in the testosterone-induced acceleration of sexual maturation.

Developmental changes in the hypothalamic mRNA levels of nucleobindin-2 (NUCB2) and their sensitivity to fasting in male and female rats.

Nesfatin-1 is a central anorectic peptide derived from the precursor protein nucleobindin-2 (NUCB2). In the present study, the changes in hypothalamic NUCB2 mRNA expression and their responses to food deprivation during the neonatal to pre-pubertal period (postnatal days 10, 20, and 30) were evaluated in male and female rats. The rats' serum leptin levels were also measured because NUCB2 mRNA expression is positively regulated by leptin.

The expression of orexigenic and anorexigenic factors in middle-aged female rats that had been subjected to prenatal undernutrition.

Fetal growth retardation, which affects short- and long-term fetal brain development, is associated with metabolic, hematological, and thermal disturbances, which can increase the risk of metabolic syndrome later in life. Orexigenic and anorexigenic factors regulate food intake and energy expenditure. We studied how the expression of these factors was affected by food deprivation (FD) in middle-aged female rats that had been subjected to prenatal undernutrition.

Prenatal undernutrition results in greater lipopolysaccharide-induced changes in hypothalamic TNF-α expression, but does not affect the equivalent changes in the serum levels of luteinizing hormone and testosterone, in adult male rats.

Immune stress can cause reproductive dysfunction. Some hypothalamic factors such as pro-inflammatory cytokines play pivotal roles in reproductive disorders under immune stress conditions. Recently, it has been reported that prenatal undernutrition affects not only metabolic functions, but also the responses of physiological functions to immune stress in adulthood.

Effects of LPS injection on the hypothalamic and testicular mRNA expression levels of reproductive factors in male rats.

Objectives: In the hypothalamus, kisspeptin and RFamide-related peptide (RFRP) regulate gonadotropin-releasing hormone expression. Kisspeptin and RFRP are also found in the testes and might play roles in steroidogenesis and spermatogenesis.

Design And Results: The present study demonstrated that the hypothalamic mRNA expression level of the kisspeptin receptor was decreased by the injection of lipopolysaccharide (LPS) (500 μg/kg) in male rats, and it was suggested that such changes might contribute to reductions in serum luteinizing hormone levels.

Developmental changes in the hypothalamic mRNA levels of prepro-orexin and orexin receptors and their sensitivity to fasting in male and female rats.

Orexin, which is also called as hypocretin (Hcrt), a product of the prepro-orexin (pp-orexin//Hcrt) gene, affects various physiological and behavioral functions, such as the sleep-wake cycle and appetite. The developmental changes in the hypothalamic mRNA levels of pp-prexin and the orexin receptors OX1R and OX2R and their sensitivity to fasting were evaluated in both male and female rats. During development, hypothalamic pp-orexin/Hcrt mRNA expression increased in both male and female rats, whereas hypothalamic OX1R mRNA expression decreased in both sexes.

The suppressive effect of immune stress on LH secretion is absent in the early neonatal period in rats.

Some physiological functions display weak responses to stress in the early neonatal period; i.e., they exhibit stress hyporesponse periods.

The effects of ovariectomy and LPS-induced endotoxemia on resistin levels in female rats.

Resistin is involved in the inflammatory response, as well as in insulin resistance. In rodents, resistin levels are partially regulated by ovarian hormones. Thus, ovariectomy-induced changes in resistin levels and their response to lipopolysaccharide (LPS)-induced septic stress were evaluated.

Prenatal undernutrition increases the febrile response to lipopolysaccharides in adulthood in male rats.

It has been reported that prenatal undernutrition affects the development of the peripheral immune system. In this study, the effects of prenatal undernutrition on the febrile response and hypothalamic innate immune system were evaluated in male rats. Pregnant rats were divided into normally nourished (NN) and undernourished groups (UN).