Progesterone influence on gerbil (Meriones unguiculatus) prostate: interactions with estrogen and testosterone

Author(s)

Ricardo Alexandre Fochi

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2013-02-25

Examining board members

Sebastião Roberto Taboga; Classius de Oliveira; Daniele Lisboa Ribeiro; Wagner José Fávaro; Luis Antonio Justulin Junior

• Advisor: Sebastião Roberto Taboga

Abstract

The prostate is a gland of reproductive system that arises from the urogenital sinus, being located around the urethra below the bladder. The existence of this gland is not exclusive of the male reproductive system, being found in females of various species, including rodents and humans. In the male, it can be highly developed due to the increased amount of the testosterone, and although poorly developed in females, due to the low quantity of this hormone, it is a functional gland. The prostate of female gerbils has a paraurethral location, showing a closer contact with the proximal and medial urethra wall, being homologous to the ventral prostate of male rats. This study evaluates the morphofunctional aspects of the prostate gland in males and females, regarding the influence of progesterone, and their interactions with estradiol and testosterone. For this, male and female gerbils were surgically castrated in early pubertal period, at 45 days of age. At 90 days of age, the gerbils received subcutaneous doses of progesterone alone or associated to testosterone or estradiol during 14 days. In castrated animals of both sexes, prostate showed a regressed morphology, with a significant reduction in its secretion capacity, the amount of androgen receptor cells (AR) and estrogen receptor ? (ER?), but without changing the labeling for estrogen receptor ? (ER?). Thereby, surgical castration was very important, since it allowed mimetize a prostatic environment with low hormone levels. In both sexes, the administration of progesterone alone could reverse some of these effects with a considerable secretion improvement, but structurally these changes occurred in a moderate way. In these animals, we observed a significant increase of ER ? and ?, besides the presence of progesterone receptor (PR) cells. Regarding ARs, it was shown that progesterone can have inductor or inhibitory characteristics depending on its concentration. The treatment with progesterone plus estradiol and progesterone plus testosterone triggered a more intense prostate restructuration in male and female, resulting however in a hypertrophy and hyperplasia of the glandular epithelium and stroma, besides recovery of the alveoli amplitude and pattern of cellular secretion. These characteristics, however, were followed by the development of prostatic lesions like intraepithelial neoplasia and cellular desquamation. The progesterone and estradiol interaction also upregulated the AR, ER? and ER?, however had no effect on the PRs when compared to the animals treated with progesterone alone. In addition, in these animals there was a marked increase in cellular proliferation, which was counterbalanced by increased cell death. In animals of either sex treated with progesterone and testosterone, the prostate also became developed and showed an increase of AR-positive cells and apoptotic index, although there was a reduction of ER?, ER? and PR. Thus, it is reasonable to conclude that the female and male prostate behaves similarly after the progesterone, estradiol and testosterone administration. Moreover, although the progesterone has reasonable structural effects on the prostate gland, its interaction with estrogen and testosterone can intensificate these effects, but do not recover a homeostatic environment similar to that of intact animals. The progesterone also proved to be a potential regulatory factor of the proliferative and apoptotic activity, opposing the effects of testosterone and estradiol. Another important finding is that progesterone can induce or inhibit the presence of ARpositive cells in the gland, and this functional dualism is the result of dose-dependent effect of this hormone on the prostate (AU)

• FAPESP's process: 08/11386-9 - Influence of the progesterone and of their interactions with the estrogen and testosterone on the gerbil (Meriones unguiculatus) prostate
• Grantee: Ricardo Alexandre Fochi
• Support Opportunities: Scholarships in Brazil - Doctorate