The Effect of Oral Administration of Sucrose on the Turnover Rate of Plasma Free Fatty Acids and on the Esterification Rate of Plasma Free Fatty Acids to Plasma Triglycerides in Normal Subjects, Patients with Primary Endogenous Hypertriglyceridemia, and Patients with Well Controlled Diabetes Mellitus

Abstract

12 patients with primary endogenous hypertriglyceridemia (type IV according to Fredrickson et al. (1967), plasma triglyceride (TG) concentration 239-3680 mg/100 ml, k-value after intravenous glucose load above 1.15), 9 normal subjects (plasma-TG concentration 32-140 mg/100 ml, k-value above 1.3) and 6 patients with diabetes mellitus, well controlled by tolbutamide (plasma-TG concentration 112-330 mg/100 ml, k-value below 1.1) were investigated.

In the fasting state, there was no significant difference in the concentration of free fatty acids (FFA), in the turnover rate of FFA in plasma, as well as in the absolute and fractional esterification rate of plasma-FFA to plasma-TG.

During oral administration of sucrose (1 g/kg/hour), the hyperlipemics and the diabetics showed a significantly higher concentration of plasma-FFA than the normals. The administration of sucrose caused a decrease in the turnover rate of plasma-FFA and in the esterification rate of plasma-FFA to plasma-TG, but the latter was significantly higher in the hyperlipemics and in the diabetics than in the normals. In each of the 3 groups, the fractional esterification rate of plasma-FFA to plasma-TG was higher than in the fasting state. There was no difference in the fractional esterification rate of plasma-FFA to plasma-TG between the 3 groups of subjects. Significant positive correlations between the concentration of plasma-FFA and the turnover rate of plasma-FFA as well as between the concentration of plasma-FFA and the esterification rate of plasma-FFA to plasma-TG could be demonstrated for all persons of the 3 groups. It is suggested, that the higher production rate of plasma-TG from plasma-FFA in the hyperlipemics and in the diabetics can be regarded as the result of the decreased FFA lowering effect of sucrose in these two groups.

In the fasting state as well as during sucrose loading, the hyperlipemics showed the same esterification rate of plasma-FFA to plasma-TG, but an enormously higher plasma-TG concentration than the diabetics. Assuming that endogenous plasma-TG are produced mainly by esterification of plasma-FFA, these findings indicate that the primary defect which is responsible for the elevated plasma-TG concentration in primary endogenous hypertriglyceridemia, is an insufficient removal of TG from the plasma, not only in the fasting state, but also during acute sucrose loading.