Articles

Reproductive neuroendocrinology in the caprine species

Abstract

Hypothalamic activity commands the episodic discharge of gonadotropins in the general circulation. Pulses of LH, secreted by the pituitary and defined with their frequency and amplitude, stimulate the release of testosterone by the testis in the male and of estradiol and progesterone by the ovary in the female. FSH appears to be secreted more continuously in a non episodic manner. In the female goat, modulation of the negative and positive feed-back of progesterone and estradiol on the hypothalamo-pituitary axis plays a key role in the regulation of the differents events of the oestrous cycle. Progesterone priming is not necessary for the induction of estrous behaviour by estradiol. In both sexes, seasonality of neuroendocrine activity is responsible for the large seasonal variations in sexual activity. Enhancement of the negative feed-back of estradiol on the hypothalamo-pituitary axis is responsible for the low gonadotropin activity during anestrus. This effect is mediated by the photoperiod which acts on the central nervous system by the modification of the duration of night-time melatonin secretion. Changes in the feeding regime also cause modifications in the gonadotropic activity. Presence of males causes an immediate increase in the frequency of LH pulses in the females.

Authors


P. CHEMINEAU

philippe.chemineau@inra.fr

Affiliation : INRA Physiologie de la Reproduction 37380 Nouzilly

Country : France


J.A. DELGADILLO

Affiliation : Universidad Autonoma Agraria Antonio Narro, Carretera a Sta Fé y Periférico, Apartado Postal 940, Torreon, Coahuila, México

Country : Mexico

Attachments

No supporting information for this article

##plugins.generic.statArticle.title##

Views: 321

Most read articles by the same author(s)

1 2 > >>