Acute Testosterone Deficiency Alters Adipose Tissue Fatty Acid Storage.

Abstract

Although the long-term effects of testosterone on adipose tissue lipid metabolism in men have been defined, the short-term regulation of these effects is not well understood. We examined the effects of acute testosterone withdrawal on subcutaneous abdominal and femoral adipose tissue fatty acid (FA) storage and cellular mechanisms. This was a prospective, randomized trial. Mayo Clinic Clinical Research Unit. Thirty-two male volunteers ages 18 to 50 participated in these studies. Volunteers were randomized to receive (1) no treatment (control), (2) injections (7.5 mg) of Lupron®, or (3) Lupron and testosterone (L+T) replacement for 49 days, resulting in 4 weeks of sex steroid suppression in the Lupron group. We measured body composition, fat cell size, adipose tissue meal FA and direct free FA storage, lipoprotein lipase (LPL), acyl coenzyme A synthetase (ACS), diacylglycerol acyltransferase activities, and CD36 content. Compared with control and L+T groups, acute testosterone deficiency resulted in greater femoral adipose tissue meal FA storage rates, fasting and fed LPL activity, and ACS activity. These results suggest that in men, testosterone plays a tonic role in restraining FA storage in femoral adipose tissue via suppression of LPL and ACS activities. FA storage mechanisms in men appear sensitive to short-term changes in testosterone concentrations.