Insulin effects on glucose kinetics in non-insulin-dependent diabetic patients with secondary failure to hypoglycaemic agents: role of different modes and rates of delivery.

OBJECTIVES: This study aimed at investigating the effects of pulsatile and continuous insulin delivery on glucose kinetics in non-insulin-dependent (type 2) diabetic patients with secondary failure to oral hypoglycaemic agents. METHODS: Seven type 2 diabetic patients underwent a 585 minute glucose-controlled glucose intravenous infusion using the Biostator. The endogenous pancreas secretion was inhibited by somatostatin. Three experiments were performed in each patient on different days and in random order. In all cases, glucagon was replaced (58 ng/min). The amounts of insulin infused were: a) 0.15 mU/kg x min continuously; b) 0.20 mU/kg x min continuously and c) 1.0 mU/kg x min in 2 minute pulses every 13 minutes. D-[3-3H]-glucose infusion allowed determination of glucose kinetics. RESULTS: Infusion of identical amounts of insulin (A vs C) demonstrated that pulsatile insulin delivery exerted greater metabolic effects (higher glucose infusion rate and, mainly at the beginning of the experiment, lower endogenous glucose production) than continuous infusion; furthermore pulsatile insulin delivery (C) exerted metabolic effects similar to those of a greater dose of insulin (B) infused continuously. CONCLUSIONS: In type 2 diabetic patients with secondary failure to oral hypoglycaemic agents, pulsatile insulin delivery exerts greater metabolic effects than continuous hormone delivery.