Associations of Gonadotropin-Releasing Hormone Receptor (GnRHR) and Neuropeptide Y(NPY) Genes’Polymorphisms with Egg-Laying Traits in Wenchang Chicken

Single nucleotide polymorphisms （SNP） of chicken gonadotropin-releasing hormone receptor （GnRHR） and neuropeptide Y （NPY） were selected to identify the genotypes of Wenchang （Chinese indigenous breed） chicken with restricton fragment length polymorphisms. The associations of the SNPs with the total egg production （NE）, average days of continual laying （ADCL）, and number of double-yolked eggs （DYE） traits were analyzed. The frequency of restriction enzyme A/a alleles in the population was for GnRHR 0.69 （Bpu1102 Ⅰ A） and 0.31 （Bpu1102 Ⅰ a） and for NPY 0.46 （Dra Ⅰ B） and 0.54 （Dra Ⅰ b）. Trait data from a total of 120 hens, which were purebred introduced from Hainan Province, China from one generation were recorded. Two significant effects of genes＇ marker were found： for GnRHR and number of eggs （dominant; t= 2.67, df= 116） and NPY and number of eggs （additive; t= 1.97, df= 116）. The current research supports the effects of GnRHR and NPY genes on egg-laying traits of chickens.

Immunohistochemical Localization and Receptor Expression of Gonadotropin-Releasing Hormone in Pituitary of Guangxi Swamp Buffaloes

[ Objective] To locate gonadotropin-releasing hormone （GnRH） in pituitary of Guangxi swamp buffaloes and to provide a theoretical ba- sis for cloning and sequence analysis of GnRH receptor gene. [ Method] GnRH in pituitary were immunohistochemically stained by avidin biotin complex method. The GnRH expression was analyzed with image system. The GnRH receptor gene was amplified by real-time PCR. [ Result] Many GnRH positive cells were detected in pars distalis of adenohypophysis. GnRH were distributed in cytoplasm but not in nuclei. No positive sig- nal was observed in neurohypophysis. In addition, the GnRH receptor gene, 920 bp in size, was amplified. [ Conclusion] A large number of GnRH and GnRH receptor were found in pars distalis of adenohypophysis, which indicates that anterior pituitary is an important tissue for functions of hypo- thalamus-pituitary-gonadal axis and other endocrine axes.

Kisspeptin regulates gonadotropin-releasing hormone secretion in gonadotropin-releasing hormone/enhanced green fluorescent protein transgenic rats

Kisspeptin is essential for activation of the hypothalamo-pituitary-gonadal axis. In this study, we established gonadotropin-releasing hormone/enhanced green fluorescent protein transgenic rats. Rats were injected with 1, 10, or 100 pM kisspeptin-10, a peptide derived from full-length kisspeptin, into the arcuate nucleus and medial preoptic area, and with the kJsspeptJn antagonist peptJde 234 into the lateral cerebral ventricle. The results of immunohistochemical staining revealed that pulsatile luteinizing hormone secretion was suppressed after injection of antagonist peptide 234 into the lateral cerebral ventricle, and a significant increase in luteinizing hormone level was observed after kisspeptin-10 injection into the arcuate nucleus and medial preoptic area. The results of an enzyme-linked immunosorbent assay showed that luteinizing hormone levels during the first hour of kisspeptin-10 infusion into the arcuate nucleus were significantly greater in the 100 pM kisspeptin-10 group than in the 10 pM kisspeptin-10 group. These findings indicate that kisspeptin directly promotes gonadotropin-releasing hormone secretion and luteinizing hormone release in gonadotropin-releasing hormone/enhanced green fluorescent protein transgenic rats. The arcuate nucleus is a key component of the kisspeptin-G protein-coupled receptor 54 signaling pathway underlying regulating luteinizing hormone pulse secretion.

Studying the nature of ascending-descending-floating-sinking of Chinese medicines based on gonadotropin-releasing hormone

OBJECTIVE:To explore the nature of ascendingdescending-floating-sinking of Traditional Chinese Medicine on normal rats using gonadotropin-releasing hormone(GnRh).METHODS:Normal male Sprague-Dawley rats were orally administered six floating Chinese medicines and seven sinking Chinese medicines for 14 d.Then,GnRh and relevant indicators were detected.Initially,the different effects of floating and sinking drugs on the body were explored.To verify the effects of floating and sinking drugs on the body,normal rats were orally administered Mahuang(Herba Ephedra Sinica)and Tinglizi(Semen Lepidii Apetali)for 14 d.Then,GnRh antagonists were administered.We observed the changes of relevant indicators and clarified the correlation between GnRh and the laws of floating and sinking.RESULTS:Floating Chinese medicines significantly increased the testicular coefficients;GnRh level in the serum;the protein level of GnRh receptor(GnRhR)in the testis;and the mRNA levels of androgen receptor(AR),small C-terminal domain phosphatase(SCP)3,SCP2,SYCE1,SMC1 B,SMC3,and Rec8(P<0.01 or<0.05).Sinking Chinese medicines did not react similarly,while GnRh antagonists blocked the regulatory effect of Mahuang(Herba Ephedra Sinica)but did not affect Tinglizi(Semen Lepidii Apetali).CONCLUSIONS:GnRh may be closely related to the nature of ascending-descending-floating-sinking of Chinese medicine.Floating Chinese medicines may promote their medicinal properties by regulating Gn RH level;however,sinking Chinese medicines did not affect GnRh level.