Repercussion of prolactin and its inhibitor, bromocriptine, in the epithelial-stromal interaction of the Mongolian gerbil prostate

Author(s)

Marianna Zanatelli

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2016-11-03

Examining board members

Sebastião Roberto Taboga; Wagner José Fávaro; Taize Machado Augusto; Alexandre Bruni Cardoso; Murilo Vieira Geraldo

• Advisor: Fernanda Cristina Alcântara dos Santos; Sebastião Roberto Taboga

Abstract

The prostate is an accessory gland of the reproductive system responsible for secretion and storage of a liquid with nutritious properties. It is found in most mammals and, in recent years, the female prostate has been studied in order to understand their role in reproductive function and reproductive tract pathologies. Steroid hormones are responsible for the growth, proliferation and development of the gland, but they are not the only ones involved in homeostasis or in promotion of tissue lesions. Prolactin is a polypeptide hormone with pituitary and extrapituitary synthesis, and more than 300 biological activities in the body, among them, functions involved with reproduction. However, their exact role in maintaining prostate is not well defined. Thus, this project aimed to evaluate the effect of prolactin and its inhibitor, bromocriptine, on prostate histophysiology of adult females and males Mongolian gerbils (Meriones unguiculatus) intact and castrated, in order to establish relations between prolactin and steroid hormones. The animals were subjected to administration of exogenous prolactin or bromocriptine, on two treatment periods, 3 and 30 days. The ventral prostates of males and prostatic complex of females were evaluated by histological, morphometric-stereological and immunocytochemistry analysis. The results show that prolactin and bromocriptine strongly influence the morphology of the female and male gerbil prostates, promoting the emergence of PIN cribriform lesions in the gland already after 3 days of administration in intact animals. After 30 days of exposure to prolactin, the gland showed no such lesions and the organ morphology was almost reestablished. Bromocriptine produced in gland effects like-prolactin administration, probably because it was not effective in inhibiting the action of extrapituitary prolactin in tissue. Prolactin and its receptor were identified in female and male prostates by immunocytochemistry, located mainly in the apical region of epithelial cells. In the female prostate, prolactin increased the expression of estrogen receptors ER? and ER? when administered after castration, and did not alter the androgen receptor (AR). In the male prostate, prolactin increased immunostaining of its receptor (PRLR), of AR, ER? and ER? in intact animals, but not in castrated animals, indicating that this hormone has a synergistic relationship with androgens. Despite to not prevent the regression of prostatic acini after castration, prolactin administration softened the atrophic effects of hormone ablation in female and male gland without causing the appearance of lesions. Thus, the prolactin presented functions sometimes related to the presence of steroid hormones, sometimes activated by their absence. Different phenotypes of secretory cells were identified in the epithelium of female prostate. The mucinous, clear, basophils, droplets, spumous, ciliated and neuroendocrine cells, differentiated by cytochemical and immunocytochemical features, were changed in number as the experimental conditions of hormone ablation by castration and administration of exogenous prolactin and bromocriptine, showing that the female prostate responds to the conditions of hormonal imbalance managing the activity of specific epithelial cells (AU)

• FAPESP's process: 12/00695-6 - Repercussion of prolactin and its inhibitor, bromocriptine, in epithelial-stromal interactions of Mongolian gerbil prostate
• Grantee: Marianna Zanatelli
• Support Opportunities: Scholarships in Brazil - Doctorate