| Taurine as a conditionally essential amino acid of humans and animals is one of the abundant free amino acid in reproductive organs and cells of female animal. Study has showed that taurine has close relationship with ovarian mature and the synthesis and release of estrogen, however the mechanisms of which is unclear. Female rats were used in this experiment, the mRNA and protein expressions of cysteine sulfinate decarboxylase(CSD),cysteine dioxygenase (CDO) and taurine transporter(TAUT) in the hypothalamus pituitary gonad axis of female rat were detected,The regulatory mechanisms of taurine on the secretion of reproductive hormone were analyzed by taurine administration.The influence of taurine on the hormone secretion and the expressions of correlated factors in the hypothalamus cells, pituitary cells and ovary cells were detected in vitro. By culturing in vitro follicle and oocyte, the effects of taurine on the development of follicles and the maturation, the fertilization and the merogenesis of oocytes were analyzed. The influence and mechanisms of taurine on the reproduction engender were discussed in order to provide theoretical basis for women or female animal reproduction. The results are described as follows:(1)The sequence of the CSD gene from the hypothalamus-pituitary-ovarian axis, the sequence of the CDO gene in the hypothalamus,the full length sequence of the CDO gene in ovary and the sequence of the TAUT gene in the hypothalamus-pituitary-ovarian axis have been successfully cloned, which have homologous rate(above 96%)compared with nucleotide sequence and amino acid sequence in liver gene. The protein expression of CSD,CDO and TAUT have been found in the hypothalamus-pituitary-ovarian axis, and the protein expressions of CDO、CSD and TAUT were mainly distributed in the cainterna leydig cell layer. The results showed that taurine could be synthesized in the hypothalamus, pituitary and ovarian by CSD pathway, and these organs have the ability of transporting exogenous taurine into the cell.(2)Taurine exerted influence on the secretion of gonadotrophin releasing hormone(GnRH), prolactin(PRL), luteotrophic hormone(LH), estradiol(E2) and progesterone(P) during different estrus cycle, but the effect of taurine on follicle stimulating hormone(FSH) is still unclear. The results showed that taurine can regulate the reproductive function of female rats by acting on the hypothalamus-pituitary-ovarian axis.(3) Taurine can promote the secretion of GnRT in hypothalamus, PRL and LH in the adenohypophysis, E2 and P in the ovary of female rats, it can also increase the mRNA expressions of the luetinizing hormone receptor (LHR) in the endocardial cells, (3-hydroxy steroid dehydrogenase (3β-HSD) and 17β-hydroxy steroid dehydrogenase (17(3-HSD), as well as promote the mRNA expressions of the follicle stimulating hormone receptor (FSHR) and CYP-19A-1 in the granule cells. The result showed that taurine can promote the synthesis and secretion of sex hormones by increasing the quantity of FSHR and LHR in ovary and promoting the expressions of the key enzymes of sex hormons.(4) Taurine can increase the diameter growth of ovarian follicle in vitro promote the secretion of estradiol, and also have promotional effects on the MⅡ formation, fertilization and merogenesis of cultured oocytes. The results showed that taurine can compound the growth of follicle and the oocyte maturation, fertilization and cleavage rate.The experiment results showed that taurine can be biosynthesized in the hypothalamic-pituitary-gonadal axis, which have the ability of transporting the exogenous taurine into the cell. Taurine can regulate reproductive female rats by strengthening the function of hypothalamic-pituitary-gonadal axis. |
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