Testosterone acts directly at androgen receptors and also exerts potent actions following 5α-reduction to dihydrotestosterone (DHT). Finasteride (type II 5α-reductase inhibitor) lowers DHT and is used to treat benign prostatic hyperplasia. However, it is unknown whether elevated DHT mediates either beneficial musculoskeletal effects or prostate enlargement resulting from higher-than-replacement...

OBJECTIVE In this study, we determined the effects of graded doses of testosterone on muscle fiber cross-sectional area (CSA) and satellite cell number and replication in older men. PARTICIPANTS Healthy men, 60-75 yr old, received a long-acting GnRH agonist to suppress endogenous testosterone production and 25, 50, 125, 300, or 600 mg testosterone enanthate im weekly for 20 wk. METHODS Immu...

Testosterone increases fat-free mass (FFM) in men infected with human immunodeficiency virus (HIV), but its effects on muscle performance, physical function, mood, and quality of life are poorly understood. Sixty-one HIV-infected men with weight loss were randomized to receive weekly intramuscular injections of 300 mg of testosterone enanthate or placebo for 16 wk. The primary outcome of intere...

OBJECTIVE To test the hypothesis that oral desogestrel (DSG) plus testosterone would uniformly and rapidly suppress sperm concentrations in young men as effectively as levonorgestrel (LNG) plus testosterone and cause less high-density lipoprotein (HDL) suppression and weight gain. DESIGN Single-blind, randomized trial. SETTING VA Puget Sound and University of Washington, Seattle, Washington...

Testosterone enanthate (TE) is used by many athletes as a muscle builder. Previous studies showed that high concentration of the drug in plasma may affect the natural function of endocrine glands, specially the secretion of the adrenocortical hormones. The objective of the present study was to examine the effects of high concentration of TE on histometrical structure of adrenal cortex in male r...

The adequate criteria for late-onset hypogonadism (LOH) diagnosis, including serum testosterone levels, type (total or free testosterone) and duration of androgen replacement therapy, and evaluations of treatment effectiveness remain controversial. To evaluate the current status of medical treatment for LOH in Japan, the first nationwide survey were performed. A total of 35 questionnaires answe...

Gender identity disorder (GID) results from a disagreement between a person's biological sex and the gender to which he or she identifies. With respect to the treatment of female to male GID, testosterone replacement therapy (TRT) is available. The uric acid (UA) level can be influenced by testosterone; however, the early effects and dose-dependency of TRT on the serum UA concentration have not...

BACKGROUND Blood sampling is not a common practice for sports drug testing. Our aim was to investigate whether dried blood spots on filter paper could be an alternative to plasma samples for monitoring steroid profiles in dope testing. METHODS We collected dried blood spots and plasma from six healthy Caucasian subjects after an oral 120-mg dose of testosterone undecanoate (TU). Nonconjugated...

After a control phase, 10 normal men received cyproterone acetate (CPA) at a dose of 25 mg/day (CPA-25; n=5) or 12.5 mg/day (CPA-12.5; n=5) plus testosterone enanthate (TE) 100 mg/week, for 16 weeks. Throughout the study sperm counts were performed every 2 weeks, and luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone, biochemical and haematological tests were performed e...