Abstract
A simplified intravenous fat emulsion tolerance test (FETT) was established to evaluate a triglyceride rich lipoprotein metabolism.
In the present study, fractional removal rate (K2) of FETT in normolipidemic subjects (n=18) and primary hyperlipidemic patients (type IIa, IIb and IV) (n=48) was estimated. Also, the relationship between K2 value and serum lipoproteins was investigated.
FETT: After an overnight fast, the subjects were injected 0.25ml/kg body weight of 10% Intralipid®, and blood was sampled 8 times during the following 20 minutes. K2-value was determined by nephelometry as preveously reported. Serum lipoproteins were obtained by preparative ultracentrifugation according to Havel's method. Lipids in lipoprotein fractions were estimated by enzymatic methods.
Significant negative correlations were found between K2 and VLDL-TG (r=-0.50, p<0.01) as well as between K2 and VLDL-Chol (r=-0.50, p<0.01). Also, significant negative correlations were found between Log K2 and Log VLDL-TG (r=-0.62, p<0.001) as well as between Log K2 and Log VLDL-Chol (r=-0.53, p<0.01). There is no difference between K2 levels of normolipidemic subjects (11.1±3.9%/mm, nmean±SD) and K2 of type ha patients (11.3±3.6%/mm). nK2 of type IIb patients (7.6±2.3%/min) and K2 of type IV patients (7.4±3.6%/min) showed significantly lower value as compared with K2 of normolipidemic subjects and type ha patients (p<0.005). However, K2 value of some individuals in type lib and IV were similar to K2 value of normolipidemic subjects.
These results suggest that K2 in FETT might be influenced by concentration of VLDL and the catabolic disorder of TG-rich lipoprotein might exist in type IIb and IV patients, but not in type IIa patients. The results also suggest that type IIb and IV patients could be further classified in detail by means of the difference of K2 value.
