Abstract
Effects of chronic, exogenous hyperinsulinemia on very-low-density lipoprotein (VLDL)-triglyceride (TG) kinetics were studied in rats given porcine insulin subcutaneously for 2 weeks. To prevent severe hypoglycemia, they were allowed free access to sucrose solution. Therefore, two control groups were needed: chow only and crow plus sucrose. Feeding sucrose into normal rats produced an increase in serum concentrations of glucose (by 21%), insulin (by 142%) and TG (by 46%), but there was no change in the rate of TG secretion into the circulation. These findings suggest that dietary sucrose causes impairment of TG removal from the circulation. Injecting insulin into sucrose-fed rats resulted in marked hyperinsulinemia and a concomitant fall in serum glucose below the levels of both control groups. Their TG secretion rates were increased by 30% compared with the two control groups, but their TG concentrations were 50% lower than those of sucrose-fed rats. This indicated that hyperinsulinemia stimulated TG removal more than TG secretion into the circulation. The present study demonstrates that chronic, exogenous hyperinsulinemia, either directly or indirectly, stimulates VLDL-TG kinetics in the rat.
