Dehydroepiandrosterone modifies rat fatty acid composition of serum and different adipose tissue depots and lowers serum insulin levels.

Dehydroepiandrosterone (DHEA) is reported to exert beneficial effects, such as protection from cardiovascular risk and lowering serum insulin levels. Adipose tissue (AT) is a target for DHEA actions, and the hormone can also affect hepatic fatty acid (FA) metabolism. FAs are involved in the development of insulin resistance; thus, there might be a relationship between DHEA, FA, and insulin. However, few data are available regarding DHEA and FA composition, especially concerning AT. Seventeen-month old female Sprague-Dawley rats (n=11; controls: n=10) were treated with DHEA (0.5% w/w in the diet) for 13 weeks, after which serum, periovarian, mesenteric, s.c., and brown AT were analyzed for FA composition. DHEA treatment resulted in significant changes in FA profiles in serum and adipose depots, like reduced 16:1n-7 (s.c. and brown AT; P<0.01), elevated n-9 monounsaturated FA (serum and s.c. AT; P<0.05), diminished n-6 polyunsaturated FA (PUFA; general; P<0.05) and increased n-3 PUFA (brown AT; P<0.01), along with lower n-6/n-3 ratios (s.c. and brown AT; P<0.05, P<0.01 respectively). DHEA modified estimates of desaturase activities, decreasing stearoyl-CoA-desaturase markers in s.c., and brown AT (P<0.05) and increasing those of delta-6-desaturase in serum and AT (P<0.05). In addition, DHEA-treated rats showed lower serum insulin levels (P<0.05). We have demonstrated for the first time that DHEA induces significant modifications in AT fatty acid composition in vivo, mainly concerning unsaturated FAs, and changes occurred in a tissue-dependent manner. We propose that these changes may be related to the capacity of DHEA to lower serum insulin levels.