The effect of traditional Chinese medicine──Tian Gui Recipeon obesity and anovulation in androgen-sterilized rats

Objective: A traditional Chinese medicine Tian Gui Recipe (TGR) has been used to effectively treat clomiphene resistant anovulatory disease and obesity, especially in polycystic ovary syndrome (PCOS) cases with hyperinsulinemia. The effect of TGR on obesity and anovulation was investigated in androgen-sterilized rats (ASR). Methods: Female SD rats at the age of 9 days were divided into 3 groups. Group ASR (n=15): anovulation was demonstrated at the age of 70 days by vaginal smear in rats while 1. 25 mg of testosterone propionate was injected subcutaneously on its 9th neonatal day. Group A+H (n = 25): TGR were administered to ASR at the age of 80 days for 3 weeks. Rats with regular estrous cycle and ovulation after herbal treatment were included in this group. Group C (n = 15): normal ovulated rats were recruited. Around the age of 112 days or on proestrous day, all rats were sacrificed under anesthesia. Serum leptin, testosterone (T), estrogen (E2), follicular stimulating hormone (FSH), luteinizing hormone (LH) levels were measured with radioimmunoassay (RIA). Double immunofluorescent staining combined with confocal laser scanning microscope and dual in situ hybridization were carried out on sections through areas of arcuate nucleus (ARC) to determine whether estrogen receptor (ER) immunoreactivity (IR) or long form of leptin receptor (OB-Rb) mRNA were expressed in neuropeptide Y (NPY) immuno-and mRNA-containing neurons, and its relationship to proopiomelanocortin (POMC) mRNA-containing neurons. Immunohistochemistry and in situ hybridization were used to observe the levels of ER, NPY, gonadotrophin releasing hormone (GnRH) and gene expression levels on NPY, OB-Rb, POMC. Meanwhile, the criteria of energy state, including daily food intake, retroperitoneal fat depot pad and body weight, were measured and evaluated. Values of immunohistochemistry and in situ hybridization were expressed in mean optic density (MOD). Results: Seventeen out of the 25 rats (68%) in Group A+H were ovulated after herbal treatment. ASR characterized with significantly high metabolic rate, energy imbalance and obesity (P<0. 01, P<0. 01, P<0. 01). The mean serum leptin, T, E2 levels of group ASR were significantly higher than those of Group C and Group A+H (P< 0. 01,P<0. 01 ), while FSH, LH levels were lower (P<0. 01, P<0. 01 ). ERs were proved to be distributing in NPY-containing neurons, OB-Rb coexpressed in NPY-syn- thesizing neurons, and both NPY and POMC mRNA expressing neurons overlapped in ARC. Compared to Group C, levels of NPY mRNA and NPY, POMC mRNA expressions were increased (P<0. 01, P<0. 01, P<0. 01 ), OB-Rb mRNA, ER and GnRH immunoreactive expression were decreased significantly in the hypothalamus of ASR (P<0. 01, P<0. 01, P<0. 01 ). These dramatic neuroendocrine changes became normal in ovulated ASR after the herbal treatment (all P>0. 05). Conclusion: The elevated peripheral E2 caused by high T and leptin levels in ASR may down-regulate their corresponding receptors oriented on hypothalamic NPY- containing neurons respectively, therefore challenge the NPY mRNA and NPY, POMC mRNA overexpressions. The overexpression, of NPY, POMC gene transcription and translation stimulate food intake, promote the deposit of adipocyte tissue, and inhibit GnRH expression and GnRH/FSH, LH release, which contribute to the occurrence of obesity and anovulation in ASR. TGR may reverse these abnormal neuroendocrine cascades by lowering the levels of T, E2 and leptin.

Detection of Messenger RNA for Gonadotropin-Releasing Hormone (GnRH) but not for GnRH Receptors in Rat Pancreas

Although gonadotropin releasing hormone (GnRH), GnRH like molecule, and GnRH receptor (GnRH R) have been reported to exist in several tissues other than brain or anterior pituitary, there are no reports concerning GnRH or GnRH R gene expression in a normal pancreatic gland. In order to define the production of GnRH as well as GnRH R in the pancreatic gland, we examined their gene expression in various developmental stages of rat pancreas using the reverse transcriptase polymerase chain reaction (RT PCR). GnRH mRNA transcripts were found in pancreas of male and female rats at different ages, expressing at about the same level, whereas GnRH R mRNA transcripts could not be detected in any rat pancreatic gland samples. These results suggest a possible biological role of GnRH in rodent pancreas.