The relative biologic efficacy of intraperitoneal (IP) insulin administration over peripheral routes of insulin infusion for artificial delivery devices is still poorly documented. Thus, the effects of IP insulin administration have been compared with the effects of subcutaneous (SC) insulin administration upon circulating fuel metabolites, hormones and lipoproteins. In a longitudinal study, seven type I diabetic patients, aged 33 +/- 3 years, duration 16 +/- 4 years, were studied. SC intensive insulin therapy was used for 3 months, then insulin was infused IP via an implantable pump for 6 months with a similar good blood glucose control. Lipids including high density lipoprotein (HDL) cholesterol and low density lipoprotein (LDL) cholesterol, apolipoproteins A-I, A-II, and B were measured every 3 months. Although all values remained in the normal range, significant changes occurred in plasma triglycerides (63 +/- 9 SC v 88 +/- 12 mg/dL IP, P less than .05) and HDL-cholesterol (57 +/- 4 SC v 42 +/- 4 mg/dL IP, P less than .05) without concomitant changes in apolipoprotein levels. In another cross-sectional study, six of the patients consumed a standardized 400 kcal breakfast after 0.15 U/kg insulin. Eight SC insulin infused age-, glucose control- and weight-matched diabetic patients also underwent the same test using SC insulin. Six normal subjects consumed the same breakfast and served as controls. Plasma glucose, B-hydroxybutyrate, lactate, alanine, free fatty acids, free insulin and glucagon were measured for five hours after the meal. All measured parameters were comparable in both groups except free insulin and lactate.(ABSTRACT TRUNCATED AT 250 WORDS)