M. Zuber-Vogeli

Immunohistochemical study of the adenohypophysis of Typhlonectes compressicaudus (Amphibia, Gymnophiona)

SummaryThe indirect immunofluorescence method was used to identify and locate LTH-, STH-, LH-, TSH-, ACTH- and MSH-immunoreactive cells in the pituitary of Typhlonectes compressicaudus (Gymnophiona). The present study defines the histological and histochemical staining properties of each cell type identified.

Localisation par immunofluorescence de différents principes hormonaux de l'hypophyse de Nectophrynoïdes occidentalis Angel, au cours du développement embryonnaire

From premetamorphosis (end of stage Ib) of Nectophrynoides occidentalis (viviparous anuran amphibian) MSH cells are revealed in the pars intermedia of pituitary using cytoimmunofluorescence technique. At the same stage, ACTH-STH-PRL and LH cells are revealed in the pars distalis. The comparison of the order of appearance of different cell categories in the adenohypophysis (considered in the functional point of view) among the embryos of Nectophrynoides and the tadpoles of different amphibians allows the emphasis of some analogies and divergences.

Les modifications cytologiques de l'hypophyse distale des femelles de Nectophrynoïdes occidentalis angel après ovariectomie

Castration modifies quickly and strongly the pituitary gland of the female Nectophrynoides occidentalis, a viviparous anuran. However, the time-span of the sexual cycle and the state of endocrine correlations play a very important role in the pituitary response. Performed after delivery, during follicular vitellogenesis, ovariectomy provokes hypertrophy, degranulation, and vacuolization of the gonadotropic cells, which become real “castration cells.” Performed at the beginning of pregnancy, ovariectomy results in the disappearance of “prolactin” erythrosinophilic cells and in degranulation of the gonadotropic cells much quicker than in the control specimens. After the subterranean period, the pituitary glands of castrated pregnant and delivering females are very similar to those of the control specimens. In females going through their first pregnancy, ovariectomy provokes abortion. The pituitary glands of the aborted castrated females are comparable to those of juvenile females. The comparative study of the pituitary glands of aborted castrated females, pregnant castrated females, and control specimen females shows that the reactivation of the gonadotropic cells, after the subterranean period, is tied to the presence of embryos in the uterus.