The site of impaired glucose uptake in cirrhosis is uncertain. We therefore performed hyperglycemic clamps (glucose 10 mmol/L) in 10 patients with compensated alcoholic cirrhosis and impaired glucose tolerance and in six control subjects. Muscle glucose uptake was estimated in patients and controls with the forearm technique. In the cirrhotic subjects splanchnic glucose uptake was measured with hepatic vein catheterization and primed continuous infusions of indocyanine green and [6-3H]glucose. To assess insulin-independent glucose uptake and the effects of elevated nonesterified fatty acid levels on glucose uptake, we repeated the study with somatostatin to induce insulin deficiency and a nicotinic acid analog, acipimox, to inhibit lipolysis. Substrate disposal was assessed on indirect calorimetry. Despite similar stimulated insulin levels, total glucose utilization was lower in the cirrhotic subjects (3.9 +/- 0.3 vs. 8.8 +/- 1.7 mg/kg/min, p = 0.006). This deficiency was accounted for by lower nonoxidative glucose disposal (1.2 +/- 0.2 vs. 5.8 +/- 1.6 mg/kg/min, p = 0.002). Forearm glucose uptake was lower in the cirrhotic subjects (0.39 +/- 0.06 vs. 1.21 +/- 0.3 mg/100 ml/min, p = 0.001). However, splanchnic glucose uptake at 1.59 +/- 0.14 mg/kg/min was similar to that reported in other studies of normal subjects. Insulin-independent glucose uptake was normal, and acipimox had no effect on total or forearm glucose utilization. Glucose intolerance in cirrhosis is characterized by impaired peripheral insulin-stimulated non-oxidative glucose disposal. The high nonesterified fatty acid levels seen in cirrhosis most likely do not contribute to this defect. Splanchnic glucose uptake is normal in cirrhosis.