Pituitaries of rats neonatally treated with oestrogen

EFFECT OF NEONATAL OESTROGEN AND hCG TREATMENT ON THE GENITAL ORGANS OF ADULT FEMALE RATS

“…Thus, follicular development was retarded in mice treated with pituitary antigonadotropin for seven days at birth (Lunenfeld, 1969). Oestrogen administered neonatally to rats and mice has an inhibitory effect on ovarian responsiveness to gonadotropins (Leung et al, 1978;Pantic, 1981;Pantic and Lovren, 1981). The ovary of 365-day-old females neonatally treated with oestrogen contained predominantly interstitial glands and cystic follicles (Fig.…”

“…2>). Several papers demonstrated that the alteration of granulosa cells and thecal layer resulted in transformation of the preovulatory follicles into ovarian cysts and in increasing of the interstitial glands (Guraya, 1978;Pantic and Lovren, 1981;Adams, 1986). The interstitial glands were grouped in lobate form and distributed from the tunica albuginea towards the medulla.…”

“…Numerous follicles, interstitial cells and corpora lutea (CL) were Key words: Rat, ovary, uterus, vagina, oestrogen, hCG The progressive decline of regular oestrous cycles and ovulatory functions with advancing age in female rats has been well documented in previous studies (Pantic and Lovren, 1981;Ennis and Davies, 1982;Nass et al, 1984). In female rats and mice, neonatal oestrogen treatment induces changes in the reproductive tract that may persist throughout the animals life (Pantic, 1981).…”

“…These changes include a persistent rather than cyclic oestrus. During persistent oestrus, circulating oestradiol is present from many large ovarian follicles, but the luteinizing hormone surge mechanism is inhibited and ovulation does not occur (Leung, 1978;Pantic and Lovren, 1981).Studies on abnormalities of the reproductive tract indicate that oestrogens have inhibitory effects on ovarian steroidogenesis (Groen-Clevant, 1981;Wada et al, 1984). The uterus and vagina are also dependent on the effect of hormones administered to neonates (Ennis and Davies, 1982;Keys and King, 1989).…”

“…These changes include a persistent rather than cyclic oestrus. During persistent oestrus, circulating oestradiol is present from many large ovarian follicles, but the luteinizing hormone surge mechanism is inhibited and ovulation does not occur (Leung, 1978;Pantic and Lovren, 1981).…”