Expression of the androgen metabolizing enzyme UGT2B15 in adipose tissue and relative expression measurement using a competitive RT-PCR method

OBJECTIVES We have demonstrated previously that obesity in men was significantly associated with low plasma testosterone levels and higher concentrations of the androgen metabolite androstane‐3α,17β‐diol glucuronide, suggesting that androgen metabolism and elimination is increased in this condition. The objective of the present study was to investigate whether adipose tissue was a site of expression of the androgen metabolizing enzymes UDP‐glucuronosyltransferases (UGT) 2B15 and 2B17. DESIGN AND PATIENTS Subcutaneous and visceral adipose tissue was obtained from male patients subjected to various abdominal surgeries. MEASUREMENTS AND RESULTS By performing reverse transcriptase–PCR (RT–PCR) amplification of mRNA extracted from adipose tissue samples, UGT2B15 transcript was detected in both subcutaneous and omental adipose tissue while UGT2B17 transcript expression was very low, or undetectable. A quantitative, competitive RT–PCR method was established and used to quantify UGT2B15 messenger RNA. The level of UGT2B15 expression was also measured in other human tissues. Although the major sites of expression were the liver and the lung, expression in adipose tissue was similar to levels found in the prostate, testis and mammary gland. CONCLUSIONS These results demonstrate for the first time that both subcutaneous and visceral adipose tissue express androgen metabolizing enzyme UGT2B15 mRNA and further support the role of adipose tissue as a site of steroid metabolism.