Studies on the development of hypothalamic regulation of the hypophysial gonadotropic activity in rats
Daikoku, S.; Kawano, H.; Abe, K.
Archives D'anatomie Microscopique et de Morphologie Experimentale 69(1): 1-16
1980
ISSN/ISBN: 0003-9594 PMID: 7458316 Document Number: 159722
Development of the hypothalamic regulation of gonadotrophs was studied in rats. Pituitaries of rat fetuses were cut serially at 4 .mu.m in the coronal plane, and every 5th section was mounted and stained immunohistochemically with anti-hCG to the fetuses induced a remarkable disappearance of the immunoreactive materials, and as a result a numerical reduction occurred in the immunoreactive cells. These phenomena were noted even on day 18.5 of gestation. Encephalectomy of day 16.5 fetuses and daily i.p. injection of anti-LHRH serum to 17.5-19.5 day old fetuses were carried out with the purpose of blocking the effect of endogenous LHRH to fetal pituitary. Dense staining of the cytoplasm and remarkable reduction in size and in number of gonadotrophs were obtained after day 20.5 of gestation in both animal groups. The hypothalamus may start to govern the hypophyseal gonadotrophs on day 20.5 of gestation in rat.