Sequential infusions of glucose and insulin at prefixed rates: a simple method for assessing insulin sensitivity and insulin responsiveness.

In a previous study a close correlation was demonstrated between metabolic clearance rates of glucose (MCR) at an insulin infusion rate of 50 mU X kg-1 hr-1 when assessed with the isoglycaemic clamp technique and the simple, concomitant infusion of insulin and glucose at a fixed rate. To determine insulin sensitivity and insulin responsiveness it is necessary to construct insulin dose response curves by measuring insulin stimulated glucose disposal at various insulin levels. The aim of the present study was to validate a simple method for constructing insulin dose response curves in 8 healthy volunteers and 12 patients with varying degrees of glucose tolerance. Insulin mediated glucose disposal, expressed as MCR, was assessed during the steady states of sequential, concomitant infusions of insulin at 50, 150 and 500 mU X kg-1 hr-1 and glucose at 33, 44 and 55 mumol X kg-1 min-1 for 150, 120 and 120 min, respectively. The results were compared with the isoglycaemic clamp technique at the same sequential insulin infusion rates for 2 hr each. A close correlation was found between the assessments of the metabolic clearance rates of glucose with either test: tau = 0.80, tau = 0.80 and tau = 0.81 at 50, 150 and 500 mU X kg-1 hr-1, respectively. The mean (+/- SEM) MCR's of glucose, assessed with sequential glucose-insulin infusions and isoglycaemic clamp technique at insulin infusion rates of 50, 150 and 500 mU X kg-1 hr-1 were in the normal subjects.(ABSTRACT TRUNCATED AT 250 WORDS)