Obesity and type 2 diabetes do not alter splanchnic cortisol production in humans.

CONTEXT Cortisol is a potent regulator of carbohydrate, fat, and protein metabolism. OBJECTIVE The objective of the study was to determine whether obesity alone or in combination with type 2 diabetes increases splanchnic and/or leg cortisol production. DESIGN Splanchnic and leg cortisol production were measured using the hepatic and leg catheterization technique combined with infusion of D4-cortisol. SETTING The study was conducted in a General Clinical Research Center. PARTICIPANTS Nine lean nondiabetic, 10 obese nondiabetic, and 11 obese diabetic subjects were studied. INTERVENTIONS Diabetic volunteers were withdrawn from their glucose-lowering medications before study. MAIN OUTCOME MEASURES Rates of total body, splanchnic and leg cortisol, and D3-cortisol production were measured. RESULTS Rates of splanchnic cortisol production equaled or exceeded those occurring in extrasplanchnic tissues (e.g. the adrenals) in all three groups. However, because concurrent splanchnic cortisol uptake also occurred, net splanchnic cortisol release was minimal. Splanchnic cortisol production and splanchnic D3-cortisol production (an index of splanchnic 11beta-hydroxysteroid dehydrogenase type 1 activity) did not differ among the three groups. In addition, splanchnic cortisol production did not correlate with either visceral fat or endogenous glucose production. On the other hand, splanchnic cortisol uptake was greater in the obese diabetic than lean nondiabetic subjects (25 +/- 2.9 vs. 15.3 +/- 2.5 microg/min; P < 0.05). Splanchnic, but not leg, D3-cortisol production was correlated with total body D3-cortisol production (r = 0.70; P < 0.001). CONCLUSIONS Although large amounts of cortisol are produced within the splanchnic bed, implying high intrahepatic glucocorticoid concentrations, rates do not differ in lean and obese nondiabetic humans and are not influenced by the presence of type 2 diabetes mellitus. On the other hand, obesity but not diabetes increases splanchnic cortisol uptake.