Androgen Receptor Gene CAG Repeat Polymorphism and Effect of Testosterone Therapy in Hypogonadal Men in Korea

ABSTRACT

BACKGROUND: As the number of CAG repeats in the androgen receptor (AR) gene increases, transcriptional activities decrease and the effects of testosterone decline. In this study, we evaluated the importance of the CAG repeat polymorphism in regard to the effect/safety of testosterone therapy in hypogonadal Korean men. METHODS: The number of CAG repeats was determined in 42 hypogonadal men who underwent testosterone therapy for more than 24 months between December 1999 and August 2007. Body mass index, lean body mass, body fat, bone mineral density, type I collagen N-telopeptide (NTx), osteocalcin, lipid profile, hematocrit and PSA levels prior to and after 24 months of testosterone therapy were identified in our medical record review. RESULTS: Twenty-four months of testosterone therapy increased lean body mass, hematocrit, and PSA levels and reduced body fat, NTx, and HDL cholesterol levels. The mean number of CAG repeats in the AR gene was 23 +/- 3 (range, 15-29) in hypogonadal Korean men. The number of CAG repeats was not found to be associated with changes in lean body mass, body fat, NTx, HDL cholesterol, hematocrit, or PSA levels during testosterone therapy. CONCLUSIONS: No association between the number of CAG repeats in the AR gene and the effect/safety of testosterone therapy was detected in hypogonadal Korean men.