MORPHOLOGIC ASPECTS OF THE ENDOMETRIUM, IN THE ESTRUS PHASE, OF PINEALECTOMIZED RATS

summary: in this paper, it was analyzed morphologically the endometrium of pinealectomized rats, treated or not with melatonin, besides luteinizing hormones levels (lh), stimulating follicle (fsh) and prolactin (prl). the experimental groups were: i - normal rats, during three months; ii - normal rats, during six months; iii - pinelalectomized rats evaluated after three months; iv - pinealectomized rats treated with melatonin for three months; v - pinealectomized rats evaluated after six months; vi - pinealectomized rats for three months, and after treated with melatonin for more three months. in the animals from groups iii and v, the estrous ciclicity was modified, because beyond the increase in the incidence of the estrus phase, some animals developed a persistent estrus condition. in the other groups the estrous cycle was normal. the hormonal dosage showed that there was an increase in the lh levels in groups iii and v, and a small reduction in group iv. there weren't changes between groups vi and ii. the levels of fsh and prl showed themselves reduced in all animals from the pinealectomized group. however, these results didn't show statistically meaningful differences. in groups iii, v and vi the endometrium presented a normal aspect except by the presence of several endometrial glands, in most cases, dilated. in the animals that developed persistent estrus, it was observed a very fibrous stroma and rare endometrial glands, some of them presenting non-keratinazed pavement stratified epithelium. the animals in group iv showed a similar endometrium to the control groups. it was concluded that the pinealectomy can draw to the condition of persistent estrus, not producing great variation in the serumal levels of the gonadotrophic hormones, and inducing more effective changes in the glandular epithelium