Pathways of adipose tissue androgen metabolism in women: depot differences and modulation by adipogenesis

1 Molecular Endocrinology and Oncology Research Center, Laval University Medical Research Center; 2 Department of Nutrition, 3 Department of Surgery, Laval University; 4 Gynecology Unit, Laval University Medical Research Center, Québec City, Québec, Canada Submitted 17 February 2008 ; accepted in final form 20 October 2008 The objective was to examine pathways of androgen metabolism in abdominal adipose tissue in women. Abdominal subcutaneous (SC) and omental (OM) adipose tissue samples were surgically obtained in women. Total RNA was isolated from whole adipose tissue samples and from primary preadipocyte cultures before and after induction of differentiation. Expression levels of several steroid-converting enzyme transcripts were examined by real-time RT-PCR. Androgen conversion rates were also measured. We found higher expression levels in SC compared with OM adipose tissue for type 1 3β-hydroxysteroid dehydrogenase (3β-HSD-1; P < 0.05), for aldo-keto reductase 1C3 (AKR1C3; P < 0.0001), for AKR1C2 ( P < 0.0001), and for the androgen receptor ( P < 0.0001). 17β-HSD-2 mRNA levels were lower in SC adipose tissue ( P < 0.05). Induction of adipocyte differentiation led to significantly increased expression levels in SC cultures for AKR1C3 (4.7-fold, P < 0.01), 11- cis -retinol dehydrogenase (6.9-fold, P < 0.02), AKR1C2 (5.6-fold, P < 0.004), P -450 aromatase (5.7-fold, P < 0.02), steroid sulfatase (3.1-fold, P < 0.02), estrogen receptor-β (11.8-fold, P < 0.01), and the androgen receptor (4.0-fold, P < 0.0005). Generally similar but nonsignificant trends were obtained in OM cultures. DHT inactivation rates increased with differentiation, this effect being mediated by dexamethasone alone, through a glucocorticoid receptor-dependent mechanism. In conclusion, higher mRNA levels of enzymes synthesizing and inactivating androgens are found in differentiated adipocytes, consistent with higher androgen-processing rates in these cells. Glucocorticoid-induced androgen inactivation may locally modulate the exposure of adipose cells to active androgens. aldo-keto reductases; short-chain dehydrogenases; adipocyte differentiation; omental visceral fat; estrogen Address for reprint requests and other correspondence: A. Tchernof, Molecular Endocrinology and Oncology Research Ctr., Laval University Medical Research Ctr., 2705 Laurier Blvd. (T3-67), Québec, QC, Canada G1V 4G2 (e-mail: andre.tchernof{at}crchul.ulaval.ca )