PROS-1-Male Hormonal Contraceptive Regimens on Prostate Tissue

Overview

The investigators propose to examine the in vivo responses to hormonal manipulation at the molecular level directly in the tissue of interest (prostate). As in the investigators' previous, pilot study, the investigators will use the novel approach of procuring tissue specimens from normal, healthy men who might be chose to use a male hormonal contraceptive regimen were it available. The investigators will employ state of the art techniques such as laser capture microdissection (LCM) and cDNA microarrays to determine the tissue-specific consequences of male hormonal contraceptive regimens on the prostate. The results will help guide the design, safety monitoring, and selection of male hormonal contraceptive agents and provide valuable insights into prostate human prostate biology. The investigators will test the hypothesis that exogenous T administration that results in increased circulating T and dihydrotestosterone (DHT) levels will increase intraprostatic concentrations of T and its metabolite DHT. The investigators will test the hypothesis that the addition of a potent 5α-reductase inhibitor, dutasteride, or the progestin, Depomedoxyprogesterone (IM DMPA), to T administration in young and middle aged men will decrease intraprostatic DHT and increase intraprostatic T concentrations compared to T alone. The investigators will test the hypothesis that the addition of a 5α-reductase inhibitor dutasteride or the progestin IM DMPA to exogenous T, by reducing intraprostatic DHT, will decrease prostate epithelial proliferation, assessed by Ki-67 labeling index (Ki-67LI), and increase apoptosis, assessed by caspase-3 expression, and decrease androgen-regulated protein expression such as prostate specific antigen (PSA). The investigators will test the hypothesis that the addition of a 5α-reductase inhibitor or the progestin IM DMPA to exogenous T, by modifying the intraprostatic hormonal milieu, will alter prostate epithelial gene expression. Specifically, the investigators expect that the addition of the 5α-reductase inhibitor dutasteride or the progestin IM DMPA to exogenous T, will result in decreased expression of androgen-regulated genes such as PSA.

The purpose of this research study is to understand the effects of testosterone on the prostate. This knowledge will be used to help in the development of a safe male hormonal contraception. We will be administering three drugs in this study: Testim (testosterone (T) gel), dutasteride (which affects testosterone break down) and Depomedoxyprogesterone (DMPA, a progestin). We want to see their effects on levels of hormones in the blood and prostate. In addition, we will be examining the effects of these drugs on the expression of genes within the prostate. DMPA suppresses LH and FSH, which are hormones made by the pituitary gland, thus blocking the signal from the brain that causes the testes to make testosterone. Prolonged (\> 1 month) low levels of LH and FSH cause decreased sperm production in normal men. However, men may experience some side effects from the low levels of testosterone caused by DMPA; adding testosterone to DMPA eliminates these side effects while more effectively blocking LH and FSH release and sperm production. This combination of drugs is a promising male contraceptive regimen. However, the effect of these drugs on the prostate is not known. Some studies suggest that testosterone administration may promote prostate growth. Dutasteride blocks the conversion of testosterone to dihydrotestosterone and is used to treat men with enlarged prostates. Dutasteride shrinks the prostate. It is possible that combining testosterone and dutasteride may be an effective part of a male hormonal contraceptive regime. Therefore, further studies examining the effect of testosterone, DMPA and dutasteride on the prostate are needed.