RELATION BETWEEN INSULIN-RESISTANCE, HYPERINSULINEMIA, POSTHEPARIN PLASMA-LIPOPROTEIN LIPASE ACTIVITY, AND POSTPRANDIAL LIPEMIA

We examined the relation between insulin resistance, plasma glucose an d insulin responses to meals, lipoprotein lipase (LPL) activity, and p ostprandial lipemia in a population of 37 healthy nondiabetic individu als. Plasma glucose and insulin concentrations were determined at freq uent inter vals from 8 AM through midnight (breakfast at 8 AM and lunc h at noon); resistance to insulin-mediated glucose disposal was determ ined by measuring the steady-state plasma glucose (SSPG) concentration at the end of a 180-minute infusion of glucose, insulin, and somatost atin; LPL activity was quantified in postheparin plasma; and postprand ial concentrations of triglyceride (TG)-rich lipoproteins were assesse d by measuring the TG and retinyl palmitate content in plasma and the Svedberg flotation index (S())f >400 and S-f 20 to 400 lipoprotein fra ctions. Significant simple correlation coefficients were found between various estimates of postprandial lipemia and SSPG (r=.38 to .68), da ylong insulin response (r=.37 to .58), daylong glucose response (r=.10 to .39), and LPL activity (r=-.08 to -.58). However, when multiple re gression analysis was performed, only SSPG remained independently asso ciated with both postprandial TG and retinyl palmitate concentrations. These data provide evidence that insulin resistance plays an importan t role in regulating the postprandial concentration of TG-rich lipopro teins, including those of intestinal origin.