EFFECTS OF ORAL GLUCOSE ON INTERMEDIARY METABOLISM IN CONTINUOUS AMBULATORY PERITONEAL-DIALYSIS PATIENTS VERSUS HEALTHY-SUBJECTS

Objective:To explore the mechanisms and metabolic consequences of the insulin resistance of patients treated by continuous ambulatory perito neal dialysis (CAPD). Design: CAPD patients and healthy subjects inges ted a similar mean oral glucose load per kilogram of fat-free mass (FF M) [1.20 +/- 0.03 g/(kg FFM) vs 1.20 +/- 0.06 g/(kg FFM); CAPD vs heal thy subjects]. Substrate oxidation was monitored over 6 hours using in direct calorimetry. Setting: Peritoneal dialysis unit of a tertiary-ca re institutional center. Outcome Measures: Glycemia, insulinemia, subs trate oxidation. Patients: Six CAPD patients (68 +/- 5 yr) and 6 healt hy subjects (24 +/- 1 yr). The CAPD patients had similar body mass ind ex (21.4 +/- 1.3 vs 22.9 +/- 1.1 kg/m(2)), a higher percent fat (25.8% +/- 3.7% vs 16% +/- 2.2%; p < 0.05), and a lower FFM (42.2 +/- 2.2 kg vs 56.5 +/- 2.6 kg; p < 0.01) than healthy subjects. Results: The CAP D patients displayed a higher glycemic and insulinemic responses to gl ucose than did healthy subjects (p < 0.05), but similar glucose oxidat ion and storage. Lipid oxidation and plasma nonesterified fatty acids were not increased in CAPD patients versus healthy subjects, in spite of a higher adiposity. Fat oxidation was related to fat mass in CAPD p atients (r(2) = 0.77, p < 0.05) but not in healthy subjects (r(2) = 0. 05). Conclusion: CAPD patients display an insulin-resistance not expla ined by an increased lipid oxidation. The maintenance of intracellular glucose utilization at the expense of higher glycemic and insulinemic responses suggests a defective glucose transport.