Efeito do estresse agudo sobre a secreção de prolactina em ratas nulíparas e primíparas

Abstract

Prolactin is an important hormone responsible for the development of the mammary glands during pregnancy and for the production of milk during the postpartum period. It has been concluded through several studies that the production of prolactin can suffer interference from various stressors, thus resulting in increased production. Physiological factors such as reproductive experience also have an influence on prolactin, but they act in a way to decrease its production. In recent studies carried out on adrenalectomized rats, we observed that the modulation of prolactin secretion exerted by adrenal glucocorticoids does not have the same modulatory effect as a function of reproductive experience, thus indicating that primiparous females would not be as sensitive as nulliparous females to circulating levels of glucocorticoids, which could be suggestive less stress sensitivity. Other experiments carried out with nulliparous and primiparous rats on the influence of acute and prolonged stress on prolactin secretion showed that the reproductive experience does not seem to modify the serum prolactin concentration in response to acute and prolonged stress. However, the acute response could have occurred in less than an hour, the objective of this study being to study the secretion and concentrations of prolactin during the first hour after stimulation of acute stress in primiparous and nulliparous rats.