Effect of chronic stress and exogenous glucocorticoids on regional fat distribution and metabolism

It has been proposed that increased glucocorticoid hormones and decreased sex hormones affect regional fat metabolism and distribution. In the present work, it was hypothesized that chronic, uncontrollable stress, known to affect the pituitary-adrenal and pituitary-gonadal axes might, therefore, lead to differences in regional fat accumulation. In comparison with controls, male Sprague-Dawley rats stressed for 28 days, had significantly larger adipocytes. In addition, a tendency for a heavier fat pad and an increased lipoprotein lipase activity in the mesenteric depot was suggested. No significant changes were seen in epididymal, retroperitoneal, and inguinal regions. In order to study if the effects observed could be attributed to increased glucocorticoids, the response to a direct administration of supraphysiological doses of corticosterone, given either in the drinking water or via subcutaneous implantation of corticosterone pellets, was studied. Increased fat accumulation was shown in all fat depots in a dose-response fashion, but was significantly more pronounced in the mesenteric region. It was concluded that mesenteric fat tissue may respond to stress in a different manner from other fat depots. Glucocorticoids seem to be partly, but not solely, responsible for the changes observed in adipose tissue metabolism and distribution following exposure to uncontrollable stress.