Influence of the estrous cycle on prolactin secretion induced by acute stress in nulliparous and primiparous rats

Prolactin is classically considered a hormone related to the development of the mammary glands during pregnancy and the production of milk in the postpartum. The release of this pituitary hormone can be interfered by stress, resulting in increased production. Physiological factors such as reproductive experience, sum of pregnancy, childbirth and lactation, and the phase of the estrous cycle has also an action on the secretion of prolactin, reducing their serum concentration. In previous studies, we observed that reproductive experience is able to modulate the release of prolactin in response to acute stress and that this is related to the type of stress applied in rats. In this context, the aim of this work was to study the influence of the estrous cycle on prolactin serum concentrations during the first hour of induction of acute stress in nulliparous and primiparous rats. The results indicated that reproductive experience modulates the secretion of prolactin released in response to acute stress and that this is dependent on the stage of the estrous cycle