Studies Of Gonadal Development, Aromatase, Serum Sex Hormones And Hormone Receptors During The Development Of Trionyx Sinensis

One the one hand, with different age Trionyx sinensis cultured in green house as tested materials, morphological and histological changes were observed and serum testosterone and estradiol concentration were measured by ELISA. With the result that gonad development and variation characteristics of estrogen and androgen were explored. One the other hand, the experiment investigated the immunohistochemical localization of aromatase, ER, AR in the gonad during the embryonic development of T. sinensis at different incubation temperature by immunohistochemitry, and then the results were analysed and summarized. The experimental results are as follows:1. The T. sinensis cultured in green house not only grew faster but also reached maturity much earlier than wild ones. Spermatogonia were filled in the seminiferous tubules of the testes in semi-aged T. sinensis. In the seminiferous tubules of testes in one-year-old T. sinensis, there were two or three layers of spermatogonia which had a scattered distribution. For two year-old T. sinensis, there were many layers of seminiferous epithelium which included spermatogenous cells, primary spermatocyte, secondary spermatocyte, spermatid. In addition, round spermatid and elongated sperm had appeard in the seminiferous tubules. The seminiferous tubules of the testes in three-year-old T. sinensis increased obviously. Seminiferous epithelium was thinner than that of two-year-old T. sinensis. The auther could see a small amount of spermatogonia, primary spermatocyte, and secondary spermatocyte near the basement membrane and the largest number of sperm cells after metamorphosis. The ovarian follicle of semi-aged T. sinensis had developed to primary follicle phase. The ovary of one-year-old T. sinensis was at the follicular phase. The ovary of two-year-old T. sinensis was found to be at the vitellogenic phase while the three-year-old T. sinensis was at ovulatory phase.2. In female T. sinensis, the peak of testosterone levels appeared in one-year-old ones who had developed to the follicular phase. However, the testosterone levels of two-and three-year-old female T. sinensis decreased obviously. It means that the testosterone levels decreased during vitellogenic and ovulatory phase. In three-year-old female T. sinensis who were at the period of yolk deposition and mature egg formation, plasma estradiol levels came to the peak. In male T. sinensis, the peak of estradiol levels occurred in two-year-old ones whose spermatogenic activities were the most vigorous. 3. In the bipotential phase of gonadal development, AR, ER and aromatase were expressed on the surface epithelium and stromal cells, and on some sex-cord. In the sex determination phase, AR, ER and aromatase were immunoreactive on the surface epithelium and testicular cord of the differentiating testis. In addition, the cortex sometimes had positive reaction. In the differentiating ovary, AR, ER and aromatase were present on the surface epithelium, germ cell and some granular cells. During the sexual differentiation phase, they were observed on the surface epithelium, cortex, some granular cells and oogonia in the ovary. In the testis, they were immunoreactive on germinal epithelium, testicular cord and seminiferous tubules. On the whole, the expression of AR, ER and aromatase at28℃were lower than the two other temperature. AR expressed at higher level at32℃while ER expressed at higher level at30℃. The aromatase expressed higher at female-than at male-producing temperatures during the bipotential and sex determination period.