Prolactin receptors and signal pathways in the rat prostate following the increase of systemic prolactin

Abstract

The prostate is a sexual gland in charge of semen production. Several hormones regulate its function, such as prolactin (PRL) that modulates the density of prolactin receptors, and promote the proliferation, differentiation, and survival of the prostatic epithelial cells. Systemic elevation of PRL induces the increase of the epithelial height and alveolus, and pathologies as dysplasia or neoplasia; and alterations of sexual behavior. Notwithstanding, it is still unknown whether short periods of systemic PRL increase have some effects on the expression of PRL messenger or signal pathways. Thus, in this work we evaluated the effect induced by short periods of PRL elevation in sexually expert male rats. Wistar males were used. PRL elevation was induced by an adenohypophysis transplant to the renal capsule or by the intramuscular injection of 50 μg of PRL (one injection every 12 h) for 15 days. The ventral prostate was obtained and submitted to analyze the expression of the short and long PRL receptor mRNA, and the density of the signal pathways STAT 3, STAT 5, and Mapk. Results showed that the transplant decreased the long PRL receptor mRNA and increased in the short one; also, it increased the three signal pathways. The injections of PRL increased the expression of both the short and long receptor messenger; and no signal pathway was modified. As expected, no treatment altered the sexual behavior. Hence, the increase of PRL induced modifications in the expression of PRL receptor messenger as well as signal pathways. It suggests that the changes are a direct response of the hormone and not as a consequence of the quality in the execution of sexual behavior. Results suggest that the morphological changes seen in the prostate tissue are directly related to the alteration in the receptor expression and the constant activation of signal pathways. Supported by CONACyT‐Mexico grant 106531 to MEH.