Parameter of glucose metabolism and glucocorticoidal genes from two different human fat depots

The adipose and diabetic epidemic is increasing worldwide, but mechanisms behind remain widely not clear yet. One question which has to be clarified is the impact of different fat depots as putative “metabolic key players”.

We investigated 20 obese women. All participants received an extensive phenotyping including oral glucose challenge and euglycemic hyperinsulinemic clamp. Thus, estimates of myocellular and whole body insulin sensitivity were evaluated. Moreover expression levels of genes involved in the glucocorticoid metabolism (11beta-HSD1, glucocorticoid receptor alpha (GRa) and beta (GRb) and H6PDH) were analysed in subcutaneous adipose tissue biopsies from paraumbilical (SCAT-A) and gluteal (SCAT-G) region.

11beta-HSD1 expression was significantly higher in SCAT-A than in the SCAT-G (1.94 ± 0.28 vs. 1.84 ± 0.36; p < 0.05). In contrast, gene expression of GRa, GRb and H6PDH was not different between the two tissue depots. Even if the expression levels of abdominal 11beta-HSD1 were not associated with estimates of insulin resistance, abdominal GRa expression was associated with HOMA-IR (r = 0.48; p < 0.05) and myocellular insulin sensitivity (r =-0.529; p < 0.05). Moreover AUC_GLUC during the oGTT was correlated with abdominal expression of GRb (r = 0.462; p < 0.05) and H6PDH (r = 0.462; p = 0.058). However, GRa, GRb and H6PDH expression in SCAT-G was not connected to estimates of insulin resistance. Surprisingly, gluteal 11beta-HSD1 expression was associated with rather improved myocellular insulin sensitivity (r = 0.46; p < 0.05)

In summary, there were only small differences in expression levels of genes involved in glucocorticoid efficacy between abdominal and gluteal adipose tissue. Nevertheless, the impact of glucocorticoid pathway on insulin efficacy might be completely different between SCAT-A and SCAT-G.