Influence of body composition on insulin clearance

Abstract

The effect of body composition on clearance of infused insulin was studied in 21 young normal weight (relative body weight 107 .+-. 2%, of ideal mean .+-. SEM [standard error of the mean]) healthy subjects. In each subject, the percent of body weight made up of muscle and fat tissue (% muscle and % fat) were determined. Clearance of insulin was estimated during infusion of insulin at the rate of 40 mU/m2/min under maintenance of normoglycemia using the euglycemic clamp technique. Steady-state plasma insulin levels (92.6 .+-. 3.2 mU/l) correlated negatively with % muscle (r = -0.60, P < 0.010), and positively with % fat (r = 0.55, P < 0.01). Clearance of insulin was directly related to % muscle (r = 0.60, P < 0.01), and inversely related to % (r = -0.48, P < 0.010. Steady-state plasma insulin levels or insulin clearance did not correlate with relative body weight. Multiple linear regression analysis revealed a significant multivariate correlation between the rate of insulin clearance vs. % muscle and % fat (r = 0.62, P < 0.02). The changes in % muscle and % fat could predict 37% of the observed interindividual variance of insulin clearance. Apparently, insulin clearance depends on body composition and is higher in muscular than in adipose subjects. This diffference may reflect either a greater distribution space of insulin in muscular as compared to adipose subjects or an influence of body composition on insulin catabolism.