Effect of Dihydrotestosterone (DHT) on Prostate Tissue [Short Title: DHT-3]

In this study, we will examine the in vivo effects of DHT supplementation on the prostate and serum inflammatory markers at the molecular level. We hypothesize that increases in serum DHT will not increase intraprostatic DHT or prostate epithelial proliferation, and will be associated with decreases in markers of systemic inflammation. Normal, healthy, male study volunteers will be treated with either placebo gel (Group 1) or DHT gel (Group 2) for one month. Serum hormonal and inflammatory measurements will be assessed before, during, and after treatment, and the relationship between hormones and inflammatory markers associated with cardiovascular risk will be determined. Prostate biopsies will be taken after one month of treatment. Prostate tissue will be analyzed for changes in intraprostatic hormone levels as well as gene expression following treatment.

SPECIFIC AIMS:

• To determine the effect of increases in serum DHT, without concomitant increases in serum T or estrogen, on intraprostatic androgen levels.
• To determine the effect of increases in serum DHT, without concomitant increases in serum T or estrogen, on prostate epithelial gene expression.
• To determine the effect of increases in serum DHT, without concomitant increases in serum T or estrogen, on serum lipids and inflammatory markers including C-Reactive Protein [CRP], Tumor necrosis factor-alpha [TNFα], Interleukin-6 [IL-6], adiponectin, plasminogen activator inhibitor [PAI-I], and leptin.

We will test the hypothesis in normal men (rather than hypogonadal men) as a "proof of principle" investigation. A normal hypothalamic-pituitary-testicular axis and regulation, circulating T and DHT levels and intraprostatic androgen concentrations in healthy, normal men will permit optimal testing of the hypothesis. Exogenous DHT administration in normal men is expected to suppress endogenous gonadotropin and testosterone secretion, compared to more variable effects in hypogonadal men that depend on the degree of hypogonadism in these men and whether they have primary (testicular) or secondary (hypothalamic-pituitary) hypogonadism. Furthermore, intraprostatic T and DHT concentrations and 5 alpha-reductase activity (that is androgen-dependent) is expected to be more variable in hypogonadal men, depending on the degree of androgen deficiency and circulating T and DHT levels. If results in normal men support the hypothesis, subsequent studies could be performed in hypogonadal men. Because of the larger variability in circulating and probably intraprostatic androgen concentrations in hypogonadal men, these studies will require much larger numbers of subjects.

Inclusion criteria

• Males 35-55 years old
• Normal serum total testosterone (300 ng/dl-1000 ng/dl)
• Normal Luteinizing Hormone [LH] and Follicle Stimulating Hormone [FSH] levels
• Informed consent
• Taking no regular medications
• Normal baseline prostate ultrasound, hematology, and liver function tests

Exclusion criteria

• History of prostate cancer
• Prostate Specific Antigen [PSA] > 2.0
• American Urological Association [AUA] prostate symptom score > 10
• History of testosterone or anabolic steroid use in the past
• Chronic medical illness or prostate disease
• History of a bleeding disorder or need for anticoagulation
• A first-degree relative (i.e. father, brother) with a history of prostate cancer
• Abnormal digital rectal examination
• Skin condition that might interfere with or be exacerbated by DHT gel use
• History of untreated sleep apnea and/or psychiatric problems
• Participation in another study in the past 2 months
• Participating in a regular physical relationship with a pregnant woman