Increased glucose release from the liver which is responsible to a considerable extent for fasting hyperglycaemia in type 2 diabetics is associated with hepatic insulin resistance. Assessment of insulin extraction in the liver can therefore be useful in investigations of all pathophysiological conditions with deviations of glucose tolerance, or in the course of insulin secretion. The control group was formed by 8 healthy men, mean age 43.6 +/- 5.9 years, mean BMI 24.7 +/- 2.8. The authors examined also a group of 7 men with diabetes mellitus type II, mean age 46.7 +/- 5.9 years, BMI 31.4 +/- 8.9 and 6 men with hypertriacylglycerolaemia, mean age 44.2 +/- 3.1 years and mean BMI 26.2 +/- 1.4. All were examined by the intravenous glucose tolerance test with frequent blood sampling. In every sample the blood sugar level, insulin level and C-peptide level were assessed. The data were evaluated and the "hepatic insulin extraction index" was thus obtained. The "hepatic insulin extraction index" was significantly lower in type 2 diabetics throughout the experimental period (0-180 min.) as well as during individual intervals evaluated (0-20 min. and 20-180 min.). In subjects with hypertriacylglycerolaemia this index was lower only during the 0-20 min. interval. Changes of the "hepatic insulin extraction index" in patients with hypertriacylglycerolaemia do not reach the intensity recorded in diabetics and may thus indicate a milder grade of hepatic insulin resistance.