IMMUNOCYTOCHEMICAL LOCALIZATION OF SEX STEROID RECEPTORS IN THE OVARY OF CHINESE ALLIGATORS, ALLIGATOR SINENSIS

The sex steroid hormone receptors, specifically such as estrogen receptor (ER), progesterone receptor (PR) and androgen receptor (AR), play an important role during the oocyte development and oogenesis cycle of Reptilia. Immunocytochemical localization and regulations were researched in different developmental stages of the follicles of Alligator sinensis by using estrogen, progesterone and androgen receptors. In order to look for the characteristic deeply of procreation in Alligator sinensis, discuss the mechanism of hormone in the oocyte development of Reptilia farther and served as valuable referenced materials to provide scientific theory in breeding animals, we adopted histologic and immunocytochemical methods in this paper, moreover, the results of the study were observed by Laser Scanning Confocal Microscopy. The development of the ovary had seasonal changes and was divided into five periods (stageⅠ-Ⅴ) according to morphological changes of oocyte. AR, ER and PR were detected in Chinese alligator’s ovary, and positive responses positions were developed with fluorescence. The results indicated that the three kinds of hormone receptors expressed in different stages of the follicles. There were expressed strongly in the stage Ⅱ-Ⅳ follicle in April and weakly in September, ER and AR expressed in the follicle but in the cytoplasm of oocyte only in June: ER expressed broadly in the follicle cells in March and April, but ER in the stage Ⅱ-Ⅲ follicle in June distributed both in the cytoplasm of oocyte and follicle cells; immunolabelling of AR was localized weakly in the stage Ⅱ-Ⅳ follicle in March and existed double layers of follicle cells in the stage Ⅳ follicle in October; immunolabelling of PR was localized mostly cytoplasm of follicle cells in the stage Ⅱ-Ⅳ follicle in June and the follicle cells were spindle in shape with arranging erratically. The connection was osculatory between the three kinds of sex steroid hormone receptor and oocyte development. These results suggestted that follicle cells in the ovary of alligators could produce sex steroid hormone, therefore, we presumed estradiol(E) combined ER to form compound to regulate maturation of follicle cells and composition of yolk, ER expressed strongly before the oviposit but weakly after that, it illuminated that ER operated importantly during the procession of objective accumulation before spawning; AR located in the cytoplasm of the oocyte might control oocyte maturation by conbining with signal molecule in cytoplasm, and AR in the follicle cells might promote follicle development by means of integrating with testosterone (T), the ovary degenerated gradually and AR expressed weakly along with the ending of laying eggs, the function of AR decreased in a later period of oocyte development; progesterone (P) was significant in the function of follicles, luteal maintainability and ovulation, but these action came true by linking with PR, which might tune up the development and maturation of oocyte served as signal numerator. In conclusion, the three kinds of sex steroid hormone receptors related with each other and might play affection on regulating the development of follicles, vitellogenic stage and ovulation in the oocyte maturation of alligators. But particular mechanism of reptilian sex steroid hormone receptors is looked ahead.