INSULIN-SECRETION AND SENSITIVITY IN CHILDREN ON CYCLIC TOTAL PARENTERAL-NUTRITION

Background: Some children receiving total parenteral nutrition (TPN) h ave abnormal glucose tolerance. Methods: Insulin secretion and sensiti vity were studied in 12 patients, aged 5.7 to 19.4 years, receiving cy clic nocturnal TPN. Insulin secretion was measured during an IV glucos e tolerance test (IVGTT; 0.5 g/kg) followed by a hyperglycemic clamp ( plasma glucose at 10 mmol/L). Insulin sensitivity was assessed by hype rinsulinemic euglycemic clamp (insulin infusion = 1 mU/kg/min). Result s;: Patients with normal glucose tolerance receiving TPN had an insuli n response to IVGTT similar to that of normal children of the same age . Insulin levels of TPN patients were higher than those in healthy you ng adults during the hyperglycemic clamp. Whole body glucose disposal was greater in younger than in older children (range, 7.1 to 25.2 mg/k g/min), and this inverse correlation with age was statistatically sign ificant (p <.01). Two patients with abnormal glucose tolerance showed a decreased capacity to release insulin, whereas insulin sensitivity w as unchanged in one of these two patients. Two patients treated with p rednisone or octreotide had insulin levels similar to those of normal TPN children. Conclusions: The insulin response to sustained hyperglyc emia was stronger in children with normal glucose tolerance on cyclic TPN. Patients with a limited capacity to release insulin, either const itutional or acquired, may not be able to produce enough insulin in th ese conditions and develop glucose intolerance during TPN. Insulin sen sitivity was not a key factor in the alteration of glucose tolerance.