Downregulation of uncoupling protein 2 mRNA in women treated with glucocorticoids.

OBJECTIVE: Glucocorticoids are well-known regulators of energy turnover and adipose tissue metabolism. We investigated the effect of glucocorticoids on the expression of the human uncoupling protein 2 (UCP 2) gene, which has been implicated in energy expenditure. DESIGN: Prednisolone (25 mg) was administered orally daily for 7 days. Subcutaneous adipose tissue UCP 2 mRNA was measured before and after treatment. SUBJECTS: Eight healthy female subjects (age 52-63 y; body mass index 25-34 kg/m2). RESULTS: No differences in body weight, waist-to-hip ratio or plasma-values of FFA or glucose were found after prednisolone treatment, as compared to pre-treatment values under these conditions. In contrast, plasma insulin levels were significantly increased by glucocorticoid administration, 54+/-6 before vs 70+/-12 (mean+/-sem) pmol/l after treatment (P=0.028). Furthermore, using RT-competitive-PCR, the UCP 2 mRNA level in abdominal subcutaneous adipose tissue was found to be down-regulated by half (6.3+/-0.4 vs 3.1+/-0.8 amol/microg RNA, P=0.012) after glucocorticoid treatment. No difference in expression levels of the reference gene 18SrRNA was observed before, as compared to after prednisolone exposure (249+/-11 vs 248+/-30 amol/microg RNA, P=0.87). CONCLUSION: These data suggest that glucocorticoids may play a role in the regulation of UCP 2 mRNA expression in human adipose tissue in vivo.