Gonadotropin-releasing hormone II (GnRH II) mediates the anorexigenic actions of α-melanocyte-stimulating hormone (α-MSH) and corticotropin-releasing hormone (CRH) in goldfish

Intracerebroventricular (ICV) administration of gonadotropin-releasing hormone II (GnRH II), which plays a crucial role in the regulation of reproduction in vertebrates, markedly reduces food intake in goldfish. However, the neurochemical pathways involved in the anorexigenic action of GnRH II and its interaction with other neuropeptides have not yet been identified. Alpha-melanocyte-stimulating hormone (α-MSH), corticotropin-releasing hormone (CRH) and CRH-related peptides play a major role in feeding control as potent anorexigenic neuropeptides in goldfish. However, our previous study has indicated that the GnRH II-induced anorexigenic action is not blocked by treatment with melanocortin 4 receptor (MC4R) and CRH receptor antagonists. Therefore, in the present study, we further examined whether the anorexigenic effects of α-MSH and CRH in goldfish could be mediated through the GnRH receptor neuronal pathway. ICV injection of the MC4R agonist, melanotan II (80 pmol/g body weight; BW), significantly reduced food intake, and its anorexigenic effect was suppressed by ICV pre-administration of the GnRH type I receptor antagonist, antide (100 pmol/g BW). The CRH-induced (50 pmol/g BW) anorexigenic action was also blocked by treatment with antide. ICV injection of CRH (50 pmol/g BW) induced a significant increase of the GnRH II mRNA level in the hypothalamus, while ICV injection of melanotan II (80 pmol/g BW) had no effect on the level of GnRH II mRNA. These results indicate that, in goldfish, the anorexigenic actions of α-MSH and CRH are mediated through the GnRH type I receptor-signaling pathway, and that the GnRH II system regulates feeding behavior.     

Sex differences in estrogen and androgen receptors in hamster brain.

The present study was conducted to measure the levels of estrogen and androgen receptors (ER and AR, receptively) simultaneously in the anterior pituitary (AP), and various brain regions from adult male and proestrous female hamsters. Medial preoptic area (MPOA), medial basal hypothalamus (MBH), lateral hypothalamus (LH), medial forebrain bundle (MFB), and amygdala (AMG) were identified and removed from 200-microns frozen brain sections by the Palkovits punch-out technique. ER and AR were determined by the in vitro binding assay using [3H]-estradiol and [3H]-methyltrienolone as the binding ligands. In males, high levels of AR were found in the MPOA, MBH, and AP. In females, the MPOA, MBH, LH, and AP contained high levels of ER. The males exhibited significantly higher levels of AR than females in the MPOA, MBH, and LH, whereas the ER levels in these areas were higher in females. In males, ER and AR contents in the AP were higher, but the contents in the AMG were lower as compared to those of females. The calculated ER/AR ratio in MPOA, MBH, and LH were lowest in males. On the contrary, the ratio in these areas were highest in females. These data suggest that sex differences in response to estrogen and androgen may in part be due to sex differences in ER and AR contents in specific brain regions.     

Reproductive toxicologic evaluations of Bulbine natalensis Baker stem extract in albino rats

The effects of oral administration of aqueous extract of Bulbine natalensis Baker stem at daily doses of 25, 50, and 100 mg/kg body weight on the reproductive function of Wistar rats were evaluated. The indices of mating and fertility success as well as quantal frequency increased after 7 days of treatment in all the dose groups except the 100 mg/kg body weight group. The number of litters was not statistically different (P > 0.05) from the control. Whereas the absolute weights of the epididymis, seminal vesicle, and prostate were not affected, that of the testes was significantly increased. The epididymal sperm count, motility, morphology, and viscosity were not different from the control after 7 days of treatment. The male rat serum testosterone, progesterone, luteinizing hormone, and follicle-stimulating hormone significantly increased in the 25 and 50 mg/kg body weight groups, whereas the estradiol concentration decreased significantly at all the doses. The extract dose of 100 mg/kg body weight decreased the serum testosterone and progesterone levels in male rats. The prolactin concentration was not affected by all the doses. All the indices of reproduction, maternal, embryo/fetotoxic, teratogenic, and reproductive hormones in the female rats were not statistically different from that of their control except the resorption index, which increased at the dose of 100 mg/kg body weight of the extract. Histologic examination of the cross section of rat testes that received the extract at all the doses investigated revealed well-preserved seminiferous tubules with normal amount of stroma, normal population of spermatogenic and supporting cells, as well as normal spermatocytes within the lumen. The results revealed that the aqueous extract of Bulbine natalensis stem at doses of 25 and 50 mg/kg body weight enhanced the success rate of mating and fertility due to increased libido as well as the levels of reproductive hormones in male rats. The absence of alterations in the reproductive parameters of female rats at doses of 25 and 50 mg/kg body weight of Bulbine natalensis stem extract suggest that the extract is “safe” for use at these doses by females during the organogenic period of pregnancy, whereas the extract dose of 100 mg/kg body weight portends a negative effect on some reproductive functions of male and female rats.     

Neonatal agonism of ERβ impairs male reproductive behavior and attractiveness

The organization of the developing male rodent brain is profoundly influenced by endogenous steroids, most notably estrogen. This process may be disrupted by estrogenic endocrine disrupting compounds (EDCs) resulting in altered sex behavior and the capacity to attract a mate in adulthood. To better understand the relative role each estrogen receptor (ER) subtype (ERα and ERβ) plays in mediating these effects, we exposed male Long Evans rats to estradiol benzoate (EB, 10 μg), vehicle, or agonists specific for ERβ (DPN, 1 mg/kg) or ERα (PPT, 1 mg/kg) daily for the first four days of life, and then assessed adult male reproductive behavior and attractiveness via a partner preference paradigm. DPN had a greater adverse impact than PPT on reproductive behavior, suggesting a functional role for ERβ in the organization of these male-specific behaviors. Therefore the impact of neonatal ERβ agonism was further investigated by repeating the experiment using vehicle, EB and additional DPN doses (0.5 mg/kg, 1 mg/kg, and 2 mg/kg bw). Exposure to DPN suppressed male reproductive behavior and attractiveness in a dose dependent manner. Finally, males were exposed to EB or an environmentally relevant dose of genistein (GEN, 10 mg/kg), a naturally occurring xenoestrogen, which has a higher relative binding affinity for ERβ than ERα. Sexual performance was impaired by GEN but not attractiveness. In addition to suppressing reproductive behavior and attractiveness, EB exposure significantly lowered the testis to body weight ratio, and circulating testosterone levels. DPN and GEN exposure only impaired behavior, suggesting that disrupted androgen secretion does not underlie the impairment.     

Effects of quinestrol on reproductive hormone expression, secretion, and receptor levels in female Mongolian gerbils (Meriones unguiculatus)

Quinestrol, a synthetic estrogen with marked estrogenic effects and prolonged activity, has potential as a contraceptive for Mongolian gerbils. The objective of this study was to describe the effects of quinestrol on reproductive hormone expression, secretion, and receptor levels in female Mongolian gerbils. Serum and pituitary concentrations of follicle stimulating hormone (FSH) and luteinizing hormone (LH) were decreased, whereas serum concentrations of estradiol (E2) and progesterone (P4) were increased after quinestrol treatment; the effects were both time- and dose-dependent. Furthermore, quinestrol downregulated expression of FSHβ and LHβ mRNA in the pituitary gland, as well as FSH receptor (FSHR) and estrogen receptor (ER) β in the ovary. However, it up-regulated mRNA expression levels of ERα and progesterone receptor (PR) in the pituitary gland and uterus, as well as mRNA for LH receptor (LHR) and PR in the ovary (these effects were time- and dose-dependent). In contrast, quinestrol had no significant effects on the mRNA expression levels of ERα in the ovary, or the gonadotropin α (GtHα) subunit in the pituitary gland. We inferred that quinestrol impaired synthesis and secretion of FSH and LH and that the predominant ER subtype in the pituitary gland of Mongolian gerbils may be ERα. Overall, quinestrol disrupted reproductive hormone receptor expression at the mRNA level in the pituitary-gonadal axis of the Mongolian gerbil.     

Seasonal variations in the chemical composition and dry matter degradability of exclosure forages in the semi-arid region of northern Ethiopia

The present study was conduced at two sites (Tembien and Wukro) in the semi-arid region of Tigray in northern Ethiopia to investigate the seasonal dynamics in the chemical composition and dry matter digestibility of grass and browse species of exclosures. The browse species studied in Tembien and Wukro had a mean crude protein (CP) value of 166 and 117 g/kg dry matter (DM), respectively. The mean in vitro dry matter digestibility (IVDMD) coefficient and predicted metabolizable energy (ME) density of the browse species were 0.72 and 9.83 MJ/kg DM, respectively at Tembien, 0.62 and 8.38 MJ/kg DM, respectively, at Wukro. Neutral detergent fibre (NDF) and acid detergent fibre (ADF) values of the browse species varied from 192 to 437 and 127 to 391 g/kg DM, respectively. Acid detergent lignin (ADL) values ranged from 36 to 190 g/kg DM. The mean CP of the grass species in Tembien and Wukro during the long rainy season was 76 and 73 g/kg DM, respectively and values declined below a critical maintenance level during the dry and short rain seasons. Mean IVDMD and ME values for the two sites were 0.41 and 0.47, and 5.38 and 6.11 MJ/kg DM, respectively. The NDF, ADF, and lignin values of the grass species were generally above 700, 400, and 70 g/kg DM, respectively. The CP, IVDMD and ME values of the mixed grass samples differed (P<0.05) among harvesting months and values ranged from 20 to 103 g/kg DM, 0.47 to 0.72 MJ/kg DM, and 6.16 to 9.91 MJ/kg DM, respectively. The browse species could be used as useful dry season protein supplements to the N deficient native grass species. Especial emphasis should be given to propagate Maerua angolensis and Cadaba farinosa at community nursery sites. Harvesting in September, rather than the current extended harvest period that took place in October and November, can considerably improve the feeding value of native grass hay for smallholder ruminant production systems.     

T3 implantation mimics photoperiodically reduced encasement of nerve terminals by glial processes in the median eminence of Japanese quail

Photoperiodically generated triiodothyronin (T₃) in the mediobasal hypothalamus (MBH) has critical roles in the photoperiodic response of the gonads in Japanese quail. In a previous study, we demonstrated seasonal morphological changes in the neuro-glial interaction between gonadotrophin-releasing hormone (GnRH) nerve terminals and glial endfeet in the median eminence (ME). However, a direct relationship between photoperiodically generated T₃ and seasonal neuro-glial plasticity in the ME remained unclear. In the present study, we examined the effect of T₃ implantation into the MBH on the neuro-glial interaction in the ME. T₃ implantation caused testicular growth and reduced encasement of nerve terminals in the external zone of the ME. In contrast, no morphological changes were observed in birds given an excessive dose of T₃, which did not cause testicular growth. These results support the hypothesis that thyroid hormone regulates photoperiodic GnRH secretion via neuro-glial plasticity in the ME. T. Yoshimura was supported by the Program for Promotion of Basic Research Activities for Innovative Biosciences (PROBRAIN) and a Grant-in-Aid for Encouragement of Young Scientists from the Ministry of Education, Science, Sports, and Culture, Japan.     

Comparison of long-term CIDR-based protocols to synchronize estrus in beef heifers

Two experiments evaluated long-term controlled internal drug release (CIDR) insert-based protocols to synchronize estrus and compare differences in their potential ability to facilitate fixed-time artificial insemination (FTAI) in beef heifers. In Experiment 1 estrous cycling heifers (n = 85) were assigned to one of two treatments by age and body weight (BW). Heifers with T1 received a CIDR from days 0 to 14, gonadotropin releasing hormone (GnRH) on day 23, and prostaglandin F_2α (PG) on day 30. Heifers with T2 received a CIDR from days 2 to 16, GnRH on day 23, and PG on day 30. Ovaries were evaluated by ultrasonography on days 23 and 25 to determine ovulatory response to GnRH. In Experiment 2 heifers (n = 353) were assigned within reproductive tract scores by age and BW to one of four treatments. Heifers in T1 and T2 received the same treatments described in Experiment 1. Heifers in T3 and T4 received the same treatments as T1 and T2, respectively, minus the addition of GnRH. In Experiments 1 and 2, heifers were fitted with HeatWatch transmitters for estrous detection and AI was performed 12 h after estrus. In Experiment 1 heifers assigned to T1 had larger dominant follicles at GnRH compared to T2 (P < 0.01) but response to GnRH, estrous response after PG, mean interval to estrus, and variance for interval to estrus after PG did not differ (P > 0.10). AI conception and final pregnancy rate were similar (P > 0.50). In Experiment 2 estrous response after PG did not differ (P > 0.70). Differences in mean interval to estrus and variance for interval to estrus (P < 0.05) differed based on the three-way interaction of treatment length, GnRH, and estrous cyclicity status. AI conception and final pregnancy rates were similar (P > 0.10). In summary, the greater estrous response following PG and resulting AI conception and final pregnancy rates reported for heifers assigned to the two treatments in Experiment 1 and among the four treatments in Experiment 2 suggest that each of these long-term CIDR-based protocols was effective in synchronizing estrus in prepubertal and estrous cycling beef heifers. However, the three-way interaction involving treatment length, GnRH, and estrous cyclicity status in Experiment 2 clearly suggests that further evaluation of long-term CIDR-based protocols is required with and without the addition of GnRH and on the basis of estrous cyclicity status to determine the efficacy of these protocols for use in facilitating FTAI.     

Characteristics of stimulation of gonadotropin secretion by kisspeptin-10 in female goats

The aims of the present study were to clarify the effect of kisspeptin-10 (Kp10) on the secretion of luteinizing hormone (LH), follicle stimulating hormone (FSH), growth hormone (GH) and prolactin (PRL) in goats, and compare the characteristics of any response with those of the response to gonadotropin-releasing hormone (GnRH). The experiments were performed using four female goats (4–5 years old) in the luteal phase of estrous cycle. A single intravenous (i.v.) injection of 1, 5 and 10 μg/kg b.w. (0.77, 3.85 and 7.69 nmol/kg b.w.) of Kp10 stimulated the release of LH. Maximum values were observed 20–30 min after the injection. On the other hand, Kp10 did not alter plasma GH and PRL concentrations significantly. Three consecutive i.v. injections of Kp10 (5 μg/kg b.w.) or GnRH (5 μg/kg b.w.: 4.23 nmol/kg b.w.) at 2-h intervals increased both plasma LH and FSH levels after each injection (P < 0.05); however, the responses to Kp10 were different from a similar level of GnRH. The rate of decrease in LH and FSH levels following the peak was attenuated in Kp10-treated compared to GnRH-treated animals. These results show that Kp10 can stimulate the release of LH and FSH but not GH and PRL in female goats and suggest that the LH- and FSH-releasing effect of the i.v. injection of Kp10 is less potent than that of GnRH.     

Estrogenic activities of Psoralea corylifolia L. seed extracts and main constituents

Estrogenic activities of ethanol extract and its active components from Psoralea corylifolia L. were studied using various in vitro assays. The main components from ethanol extract were analyzed to be bakuchiol, psoralen, isobavachalcone, isobavachromene, and bavachinin. In a fractionation procedure, hexane and chloroform fractions showed estrogenic activity in yeast transactivation assay and E-screen assay. In yeast transactivation assay, ethanol extract, hexane, and chloroform fractions showed significantly higher activities at a concentration of 1.0 ng/ml, and bakuchiol at the concentration of 10⁻⁶ M was showed the highest activity, especially, which was higher than genistein at the same concentration. In E-screen assay, cell proliferation of bakuchiol (10⁻⁶ M) showed similar estrogenic activity with genistein (10⁻⁶ M). In ER binding assay, bakuchiol displayed the strongest ER-binding affinity (IC₅₀ for ERα = 1.01 × 10⁻⁶ M, IC₅₀ for ERβ = 1.20 × 10⁻⁶ M) and bakuchiol showed five times higher affinity for ERα than for ERβ.     

Rapid action of estradiol in primate GnRH neurons: the role of estrogen receptor alpha and estrogen receptor beta

Estrogens play a pivotal role in the control of female reproductive function. Recent studies using primate GnRH neurons derived from embryonic nasal placode indicate that 17β-estradiol (E₂) causes a rapid stimulatory action. E₂ (1 nM) stimulates firing activity and intracellular calcium ([Ca²⁺]_i) oscillations of primate GnRH neurons within a few min. E₂ also stimulates GnRH release within 10 min. However, the classical estrogen receptors, ERα and ERβ, do not appear to play a role in E₂-induced [Ca²⁺]_i oscillations or GnRH release, as the estrogen receptor antagonist, ICI 182,780, failed to block these responses. Rather, this rapid E₂ action is, at least in part, mediated by a G-protein coupled receptor GPR30. In the present study we further investigate the role of ERα and ERβ in the rapid action of E₂ by knocking down cellular ERα and ERβ by transfection of GnRH neurons with specific siRNA for rhesus monkey ERα and ERβ. Results indicate that cellular knockdown of ERα and ERβ failed to block the E₂-induced changes in [Ca²⁺]_i oscillations. It is concluded that neither ERα nor ERβ is required for the rapid action of E₂ in primate GnRH neurons.     

Effect of intracerebroventricular infusion of leptin on the secretory activity of the GnRH/LH axis in fasted prepubertal lambs

Leptin is believed to link metabolic status to reproductive processes. The aim of the present study was to investigate the effect of exogenous leptin on the secretory activity of GnRH/LH system in acutely undernourished prepubertal, female lambs. Merino lambs were randomly divided into four groups, two standard-fed and two fasted for 72 h. One standard and one fasted groups were infused intracerebroventricularly (i.c.v.) with the vehicle; the remaining standard and fasted groups were infused with leptin (25 μg/120 μl/h). Leptin was administered in series of four 1-h infusions at 30-min intervals for 3 consecutive days from 08:30 to 14:00 h. Blood samples were collected on day 0 (before infusions) and on day 3 every 10 min over a 6-h period. Immediately after the experiment, the sheep were slaughtered and brains fixed in situ. Hypothalamic and pituitary tissues were prepared for further immunohistochemical and hybridization in situ analysis. In fasted sheep, increased GnRH levels in the median eminence (P < 0.001) and LHβ levels in the pituitary cells (P < 0.001) plus decreased LHβ mRNA and LH pulsatility in blood plasma were observed (P < 0.05). In leptin-infused fasted sheep, GnRH levels in the median eminence decreased (P < 0.001), LHβ mRNA hybridization signal increased, LHβ levels decreased in the pituitary cells (P < 0.001) and LH pulsatility increased (P < 0.05) in the blood plasma. These results indicate that, in prepubertal sheep, the GnRH/LH axis is sensitive to the fasting signal, that influence of which can be reversed by leptin. Leptin cancels out the suppressing effect of fasting on LH secretion by augmentation of GnRH.     

赤腹松鼠血清性激素水平的季节差异

正季节性繁殖是动物适应环境的具体表现,也是动物维持其种群发展的重要策略。生殖激素和动物的繁殖活动关系密切,协调实现繁殖后代的机能(赖平等,2012),如配子的发生、成熟与排出及受精、妊娠、分娩与泌乳等性行为活动。例如雄性甘肃鼢鼠(Myospalax cansus)血清中睾酮(程志兴,2009)和黄山短尾猴(Macaca thibetana)血清中孕酮含量(夏东坡,2007)在交配期间显著升高,     

Pregnancy rates to timed artificial insemination in dairy cows treated with gonadotropin-releasing hormone or porcine luteinizing hormone

We compared the effects of porcine luteinizing hormone (pLH) versus gonadotropin-releasing hormone (GnRH) on ovulatory response and pregnancy rate after timed artificial insemination (TAI) in 605 lactating dairy cows. Cows (mean ± SEM: 2.4 ± 0.08 lactations, 109.0 ± 2.5 d in milk, and 2.8 ± 0.02 body condition score) at three locations were assigned to receive, in a 2 × 2 factorial design, either 100 μg GnRH or 25 mg pLH im on Day 0, 500 μg cloprostenol (PGF) on Day 7, and GnRH or pLH on Day 9, with TAI 14 to 18 h later. Ultrasonographic examinations were performed in a subset of cows on Days 0, 7, 10, and 11 to determine ovulations, presence of corpus luteum, and follicle diameter and in all cows 32 d after TAI for pregnancy determination. In 35 cows, plasma progesterone concentrations were determined 0, 3, 4, 5, 6, 7, and 12 d after ovulation. The proportion of noncyclic cows and cows with ovarian cysts on Day 0 were 12% and 6%, respectively. Ovulatory response to first treatment was 62% versus 44% for pLH and GnRH and 78% versus 50% for noncyclic and cyclic cows (P < 0.01). Location, ovulatory response to first pLH or GnRH, cyclic status, presence of an ovarian cyst, and preovulatory follicle size did not affect pregnancy rate. Plasma progesterone concentrations after TAI did not differ among treatments. Pregnancy rate to TAI was greater (P < 0.01) in the GnRH/PGF/pLH group (42%) than in the other three groups (28%, 30%, and 26% for GnRH/PGF/GnRH, pLH/PGF/GnRH, and pLH/PGF/pLH, respectively). Although only 3% of cows given pLH in lieu of GnRH on Day 9 lost their embryo versus 7% in those subjected to a conventional TAI using two GnRH treatments, the difference was not statistically significant. In summary, pLH treatment on Day 0 increased ovulatory response but not pregnancy rate. Cows treated with GnRH/PGF/pLH had the highest pregnancy rate to TAI, but progesterone concentrations after TAI were not increased. In addition, preovulatory follicle diameter did not affect pregnancy rate.     

Anti-estrogen ICI 182.780 and anti-androgen flutamide induce tyrosine phosphorylation of cortactin in the ectoplasmic specialization between the Sertoli cell and spermatids in the mouse testis

Our previous study revealed that the ectoplasmic specialization (ES) was deleted by the treatment of anti-estrogen, ICI 182.780 (ICI), and anti-androgen, flutamide (FLUT) in mouse testis. Also, expression of cortactin, an F-actin-binding protein, was decreased by the treatment of FLUT in mouse testis. Cortactin has been suggested to promote actin polymerizer at the ES in the testis, and also actin depolymerization is induced by tyrosine phosphorylation of cortactin. The present study revealed that exogenous treatment of ICI and FLUT caused the deletion of the cortactin in the apical ES and the increase of tyrosine phosphorylated cortactin in mouse testis. These results suggest that the sex hormone antagonists', ICI and FLUT, induced actin depolymerization and tyrosine phosphorylation of cortactin in the mouse testis. Also, the present study may be a key to elucidate the adverse affect exogenous compounds that affect spermiation.     

Endocrine effects of the GnRH antagonist, acyline, in domestic dogs

Gonadotrophin-releasing hormone (GnRH) antagonists may have a future role in the control of canine reproductive function. In this study, the effects of a single dose of the potent GnRH antagonist, acyline, on serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone (T) were evaluated in male dogs. Blood samples were drawn before (Day −1) and after (30, 60, and 90 min, 3, 6, 9, 12, and 24 h, and 3, 6, 9, 14, 22, and 29 d) treatment with acyline (330 μg/kg, sc); serum concentrations of FSH, LH, and T varied throughout the study period (P < 0.01, <0.05, and <0.01, respectively). Gonadotrophins decreased below pretreatment concentrations 60 min after injection, whereas T took 90 min to decrease below baseline (P > 0.05). Follicle-stimulating hormone, LH and T decreased until Day 9, when they reached their nadir at 2.0 ±1.1 ng/mL (P < 0.01), 1.2 ± 0.2 ng/mL (P > 0.05), and 0.5 ± 0.2 ng/mL (P < 0.05), respectively. Both gonadotrophins and T began increasing on Day 14 after treatment, although FSH and T serum concentrations still remained below baseline on that day (P > 0.05). Follicle-stimulating hormone and T rebounded above baseline on Day 29, whereas LH reached concentrations were similar to baseline at this time (P > 0.05). No local or systemic side effects were detected in any dog following acyline treatment. In conclusion, a single acyline treatment safely and reversibly decreased serum gonadotrophin and T concentrations in dogs for 9 d.     

Estrogenic plant consumption predicts red colobus monkey (Procolobus rufomitratus) hormonal state and behavior

Numerous studies have examined the effects of anthropogenic endocrine disrupting compounds; however, very little is known about the effects of naturally occurring plant-produced estrogenic compounds (i.e., phytoestrogens) on vertebrates. To examine the seasonal pattern of phytoestrogen consumption and its relationship to hormone levels (407 fecal samples analyzed for estradiol and cortisol) and social behavior (aggression, mating, and grooming) in a primate, we conducted an 11-month field study of red colobus (Procolobus rufomitratus) in Kibale National Park, Uganda. The percent of diet from estrogenic plants averaged 10.7% (n = 45 weeks; range: 0.7–32.4%). Red colobus fed more heavily on estrogenic Millettia dura young leaves during weeks of higher rainfall, and the consumption of this estrogenic item was positively correlated to both their fecal estradiol and cortisol levels. Social behaviors were related to estradiol and cortisol levels, as well as the consumption of estrogenic plants and rainfall. The more the red colobus consumed estrogenic plants the higher their rates of aggression and copulation and the lower their time spent grooming. Our results suggest that the consumption of estrogenic plants has important implications for primate health and fitness through interactions with the endocrine system and changes in hormone levels and social behaviors.     

The effect of a special herbal tea on obesity and anovulation in androgen-sterilized rats

A special herbal tea has been used to treat clomiphene-resistant anovulatory disease and obesity effectively, especially in polycystic ovary syndrome (PCOS) cases with hyperinsulinemia. The effect of the herbal tea on obesity and anovulation was investigated in androgen-sterilized rats (ASR). The ASR model was established by subcutaneous injection of 1.25 mg testosterone propionate to Sprague-Dawley female rats at the age of 9 days. Rats were sacrificed around 112 days of age. ASR manifested with PCO, anovulation, high food intake, elevated body weight, and obesity. Immunocytochemistry demonstrated that estrogen receptors (ER) were predominantly distributed in the cytoplasm of neuropeptide Y (NPY)-containing neurons in the preoptic area (POA), and the coexpression was also found in the nuclei and fibers of NPY-synthesizing neurons in the arcuate nucleus (ARC). Compared with that in normal control rats, NPY expression was increased, the numbers of ER in hypothalamic ARC-median eminence (ME) decreased, gonadotropin-releasing hormone (GnRH) levels in ME was decreased, serum estrogen (E2) and leptin were elevated, and follicular stimulating hormone (FSH) and luteinizing hormone (LH) levels were reduced significantly in ASR. Significantly negative correlations between NPY and ER or GnRH, and between leptin and FSH or LH were observed. A positive correlation existed between serum leptin and body weight. These metabolic-endocrine changes in ASR were normalized after feeding the herbal tea. Both obesity and hypogonadotropin were expressed in ASR. The abnormal ovarian hormone milieu (elevated E2 levels) may have enhanced NPY expression and resulted in less GnRH and gonadotropin secretion. The herbal tea reduced body weight and induced ovulation in ASR.