The role of the ovarian cycle and the effects of mitogen-induced cytokines on human prolactin gene expression in peripheral blood mononuclear cells

<b>Background</b>: little is known on the influences of normal menstrual cycle on prolactin gene expression in immune cells. Aim of the study: to determine the effects of the ovarian cycle on prolactin and its receptor expression. <b>Methods</b>: peripheral blood mononuclear cells (PBMC) were obtained from twenty-six normal menstruating women at different intervals of their menstrual cycle. The PBMC were incubated during 24 h in the presence or absence of Concanavalin-A (Con-A) and the gene expression of <i>PRL, PRLR</i> and cytokines was evaluated by qPCR. Prolactin, IL-2 and cAMP were determined in each culture by specific immunoassays. <b>Results</b>: neither <i>PRL</i> nor its receptor expression in PBMC changed significantly among groups, including the cytokines (IL-2, IL-10, and IFNG) studied. Similar results, among groups, were obtained, when <i>PRL</i> expression was stimulated by PGE2 or 8-Br-cAMP. Concanavalin A-stimulated PBMC expressed significantly less prolactin and a significant negative correlation between secreted IL-2 and PRL expression was found. The presence of anti-IL-2 antibodies in Con-A stimulated-cultures significantly increased <i>PRL</i> expression when compared to control cells regardless the hormonal status. <b>Conclusions</b>: these data suggest that the menstrual cycle does not significantly modulate or influence prolactin and cytokines gene expression in PBMC, and indicate that <i>IL-2</i> may be involved in the Con-A regulation of <i>PRL</i> expression in immune cells.