EVIDENCE FOR DECREASED SPLANCHNIC GLUCOSE-UPTAKE AFTER ORAL GLUCOSE-ADMINISTRATION IN NON-INSULIN-DEPENDENT DIABETES-MELLITUS

The role of splanchnic glucose uptake (SGU) after oral glucose adminis tration as a potential factor contributing to postprandial hyperglycem ia in non-insulin-dependent diabetes mellitus (NIDDM) has not been est ablished conclusively. Therefore, we investigated SGU in six patients with NIDDM and six weight-matched control subjects by means of the hep atic vein catheterization (HVC) technique. In a second part, we examin ed the applicability of the recently developed OG-CLAMP technique in N IDDM by comparing SGU and first-pass SGU during HVC with SGU during th e OG-CLAMP experiment. The CC-CLAMP method combines a euglycemic, hype rinsulinemic damp and an oral glucose tolerance test (75 g) during ste ady state glucose infusion (GINF). During HVC, SGU equals the splanchn ic fractional extraction times the total (oral and arterial) glucose l oad presented to the liver. For OG-CLAMP, SGU was calculated as first- pass SGU by subtracting the integrated decrease in GINF over 180 min f rom 75 g. Cumulative splanchnic glucose output after oral glucose corr elated significantly between both methods and was increased significan tly in NIDDM patients (73.1+/-5.1 g for HVC, 76.5+/-5.5 for OG-CLAMP) compared with nondiabetic patients (46.7+/-4.4 g for HVC, 57.5+/-1.9 f or OG-CLAMP). Thus, in NIDDM patients, SGU (7.4+/-2.1 vs. 37.8+/-5.9% in nondiabetic patients, P < 0.001) and first-pass SGU (4.7+/-1.7 vs. 26.5+/-5.1% in nondiabetic patients, P < 0.01) were decreased signific antly during HVC, as was SGU during OG-CLAMP (3.9+/-1.7 vs. 23.4+/-2.5 % in nondiabetic patients, P < 0.0001). SGU measured during OG-CLAMP c orrelated significantly with SGU (r = 0.87, P < 0.05 for NIDDM patient s; r = 0.94, P < 0.01 for nondiabetic patients) and first-pass SGU (r = 0.87, P < 0.05 for NIDDM patients; r = 0.84, Pt 0.05 for nondiabetic patients) during HVC. In conclusion, (a) SGU after oral glucose admin istration is decreased in NIDDM as measured by both methods, and (b) S GU during the OG-CLAMP is well-correlated to SGU and first-pass SGU du ring HVC in NIDDM. The decrease in SGU in NIDDM might contribute to po stprandial hyperglycemia in diabetic subjects.