EFFECTS OF PERITONEAL VS PERIPHERAL VENOUS INSULIN DELIVERY ON GLUCOSE-PRODUCTION AND UTILIZATION IN TYPE-I DIABETIC-PATIENTS

The relative contribution of portal vs peripheral venous (i.v.) insuli n on glucose metabolism ie production and utilisation is a question of current clinical interest with the development of new forms of therap y using the peritoneal route (i.p.) for insulin administration. Five T ype I diabetic patients underwent 2 randomly ordered, sequential, eugl ycemic, moderately hyperinsulinemic glucose clamps. The i.v. clamps co nsisted of 2-hr-insulin infusions of 0.2 and 0.4 mU/kg/min, and the i. p. clamp in 3-hr-infusions of 0.4 and 0.6 mU/kg/min, given via a chron ically placed i.p. catheter attached to an implanted insulin pump. Glu cose production and utilisation were measured using i.v. infusion of a non-radioactive tracer, [6-6 H-2] glucose. Glucose production was 2.4 +/-0.2 and 0.4+/-0.6 mg/kg/min during i.v. infusions, vs 1.4+/-0.4 and 0.5+/-0.4 mg/kg/min during i.p. sequences, ie at estimated comparable portal levels (0.4 i.p. vs 0.2 i.v., and 0.6 i.p. vs 0.4 i.v.) glucos e production was equally suppressed although the i.p. insulin infusion rates resulted in lower systemic insulin levels. Glucose utilization values were similar during 0.6 i.p. when compared to 0.2 i.v. insulin infusion ie at matched near normal systemic insulin levels. These data suggest that i.v. and i.p. insulin are as effective on glucose metabo lism, although i.p. insulin action is generated at lower systemic insu lin levels, a potential advantage for this route of insulin administra tion.