Structure and regulation of expression for LH/hCG receptor

点击翻译按钮获取中文摘要

The regulation of testicular and ovarian function by gonadotopic hormone is is mediated by specific, high-affinity receptors that are located in the plasma membrane of the respective target cells. The immediate response of target cells to the binding of these hormones are an increase in adenyl cyclase mediated by G protein. The maturation of ovarian follicles and their transformation to corpus luteum is regulated by a specific set of hormones and has been a major research area for this project.After follicle maturation, administration of hCG induce its luteinization. The appearance of corpus lutea was accompanied by increase of hCG binding. Our studies demonstrate that the effect of PMSG and hCG on ovarian gonadotropin receptors are closely related to the action of these hormones on gonadotropin receptor mRNA levels. These studies again demonstrated hCG-induced decline in LH/HCG receptor binding was associated with hCG induced down regulation of message levels.On the other hand, We have isolated and sequenced cDNA encoding the human gonadotropin receptors. Oligo-primed cDNA were prepared from human ovary polyadenylated RNAs. The library was screened with ^<32>P-labeled 2.5Kb and 2.0Kb fragment from rat LH/hCG and FSH receptor cDEIA clones. A putative extradomain of 335 and 359 amino acid precedes a region of seven transmembrane segments for the human LH/hCG receptor and FSH receptor, respectively. Mature protein should consist of 674 and 695 amino acids(75632 and 76464 daltons), and six and four potential N-linked glycosylation sites were found in the putative extracellular domain for the LH/hCG and FSH receptor.Based upon these finding, we are going to study more detail relationship between structure and function of gonadotropin receptors.