| Mounting evidence showed that the actions of sex hormones were mediated by corresponding receptor. The mouse or rat is one of the most extensively used animals in biomedical research and a clear understanding of cellular localizations and mechanism of AR and ERs on male and female reproductive system. However, few studies have documented these steroid receptors in the developing reproductive system and adrenal gland of sheep. In order to accurately identify the sites of action of oestrogens and androgens, we have proceeded to the immunohistochemistry localization of the oestrogen receptors (ERa and ERP) and the androgen receptor (AR) in the reproductive system and adrenal of sheep through gestation to adult. The studies results include four parts as followings.Experiment 1. The results showed that ERβ staining was negative in fetal testes, epididymis and efferent ductule. Whereas ERa immunoreactivity was only located in the nuclei of the efferent ductule epithelium. In addition, both ERa staining intensity and ERa positive cell number were higher (P<0.01) at day 90 and 120 of gestation, compared with that at day 70 and new birth. These results suggest that the estrogen may play important roles for ED development of sheep fetuses.Experiment 2. The three receptors AR, ERa and ERβ immunostaining were observed in the nuclear of luminal epithelium, muscle cells and stromal cell of fetal ovine uterus at 90d and 120d gestation and newborn. Strong ERα - and ERβ-immunostaining was found in the uterus of 90d gestation, the expression of ERa and ERβ decrease with the developing of fetal uteri. Weak ERa - and ERβ-immunostaining were observed in newborn fetal uterus, Specific AR immunostaining occurred mainly in granulosa and theca of primary and secondary follicle of ewe ovary, No ERa was observed in all ovaries examined. ERβ was detected in the theca and granulosa of ovary. The present findings indicate a cell-specific localization of ERa, ERβ and AR in reproductive tissues in female sheep. We propose that AR and ERβ play an important role in programming ovine fetal uterine and ovarian development. The ERa may not necessary to the development of fetal ewe ovary.Experiment 3. We have proceeded to the histological localization of the ERa and AR in the sex and accessory gland of male sheep age range from 2 month old to 8 month old. In testis, AR-immunoreaction was found in the nuclei of Leydig cell, peritubular myoid cell and Sertoli cells (except the Sertoli cell of 2 month old lamb).the epithelium cells of efferent ductules, epididymis and seminal vesicle were strongly positive for AR, while weaken staining for AR was found in stroma. AR was undetectable in all germ cell in the study. Weak AR-immunoexpression was found in the Cowper's gland. Unlike AR, ERa-immunoexpression was found only in the epithelium of efferent ductules and the stroma of seminal vesicle. in 5 month old sheep, the expression of ERa in the efferent ductules was significantly low(p<0.05) than that in 3, 4, 6, 7 and 8 month old; ERa was undetectable in the testes, epididymis and Cowper's gland through 2 month to 8 month old. These results suggested that AR have a important role in the development of testes, efferent ductules, epididymis, seminal vesicle and Cowper's gland of sheep, while ERa may involved in the development and function of efferent ductulesand seminal vesicle.Experiment 4. We have localized AR, ERa and ERβ protein in adrenal glands of ovine fetuses at different stages of gestation (60d, 90d, 120d) and newborn fetal sheep. AR-immunopositive cell was detected in the adrenal cortex, while the adrenal medulla has a few AR-positive cells; AR expression pattern has no difference between sexes. The percentage of AR-positive cell was at 60d and 90d of gestation and at day birth is significantly (p<0.01) higher than that at day 120 gestation; No ERa was detected through the gestation to newborn in the adrenal examined. While a few ERβ-positive cells were detected in adrenal of 90d, 120d gestation and newborn, there is no difference between sexe...
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