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Localization of Receptors for Sex Steroids and Pituitary Hormones in the Female Genital Duct throughout the Reproductive Cycle of a Viviparous Gymnophiona Amphibian, Typhlonectes compressicauda

by Claire Brun, Jean-Marie Exbrayat and Michel Raquet

Animals 2021, 11(1), 2; https://doi.org/10.3390/ani11010002 - 22 Dec 2020

Cited by 4 | Viewed by 2327

Abstract

Reproduction in vertebrates is controlled by the hypothalamo-pituitary-gonadal axis, and both the sex steroid and pituitary hormones play a pivotal role in the regulation of the physiology of the oviduct and events occurring within the oviduct. Their hormonal actions are mediated through interaction with specific receptors. Our aim was to locate α and β estrogen receptors, progesterone receptors, gonadotropin and prolactin receptors in the tissues of the oviduct of Typhlonectes compressicauda (Amphibia, Gymnophiona), in order to study the correlation between the morphological changes of the genital tract and the ovarian cycle. Immunohistochemical methods were used. We observed that sex steroids and pituitary hormones were involved in the morpho-functional regulation of oviduct, and that their cellular detection was dependent on the period of the reproductive cycle. Full article

(This article belongs to the Section Animal Reproduction)

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17 pages, 1354 KiB

Open AccessCommunication

Patterns of Apoptosis and Proliferation throughout the Biennial Reproductive Cycle of Viviparous Female Typhlonectes compressicauda (Amphibia, Gymnophiona)

by Michel Raquet, Claire Brun and Jean-Marie Exbrayat

Int. J. Mol. Sci. 2017, 18(1), 16; https://doi.org/10.3390/ijms18010016 - 22 Dec 2016

Cited by 6 | Viewed by 5376

Abstract

Typhlonectes compressicauda is an aquatic gymnophionan amphibian living in South America. Its breeding cycle is linked to seasons, characterized by a regular alternation of rainy and dry seasons. During a complex biennial cycle, the female genital tract undergoes a series of alternations of increasing and decreasing, governed by equilibrium of proliferation and apoptotic phenomena. Immunohistochemical methods were used to visualize cell proliferation with the detection of Ki67 antibody, a protein present in proliferative cells; terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and Apostain were performed to detect apoptotic cells on sections of ovaries and oviducts. In ovaries, both phenomena affect the germinal nests and follicles according to the cycle period. In the oviduct, the balance was in favor of proliferation during preparation for reproduction, and in favor of apoptosis when genital ducts regress. Apoptosis and proliferation are narrowly implicated in the remodeling of the genital tract and they are accompanied by the differentiation of tissues according to the phase of the breeding cycle. These variations permit the capture of oocytes at ovulation, always at the same period, and the parturition after 6–7 months of gestation, at a period in which the newborns live with their mother, protected in burrows in the mud. During the intervening year of sexual inactivity, the female reconstitutes body reserves. Full article

(This article belongs to the Collection Programmed Cell Death and Apoptosis)

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