Impaired catabolism of very low-density lipoprotein-triglyceride in a family with primary hypertriglyceridemia.
In this report, kinetic studies of plasma very low-density lipoprotein-triglyceride (VLDL-TG) were examined in five brothers (three affected and two unaffected) from a family with primary hypertriglyceridemia. Synthesis and catabolism of VLDL-TG were studied by in vivo labelling of plasma TG with 3H-glycerol, and multicompartmental analysis of the plasma die-away curves. Results of the kinetic studies revealed the following information: (1) one brother, who had the highest plasma TG level and was obese, had both overproduction and a reduced fractional catabolic rate (FCR) of VLDL-TG; (2) second brother, who had moderate hypertriglyceridemia, had a low FCR and high-normal synthesis of VLDL-TG; (3) a third, who had only mildly elevated TG, had a low FCR and normal synthesis of VLDL-TG; and (4) the two normolipidemic brothers had neither overproduction nor decreased FCR of VLDL-TG. The composition of the soluble apoproteins of VLDL was normal. The apoprotein E phenotypes were E4/3 in four brothers, and E3/2 in the fifth. We have reached the following conclusions regarding this family: (1) the common kinetic abnormality of VLDL-TG metabolism in the hypertriglyceridemic brothers was a low clearance of VLDL-TG; (2) impaired catabolism of VLDL could not be explained by the apoprotein C or E patterns; and (3) the most severe hypertriglyceridemia occurred when the decreased FCR was present in conjunction with VLDL-TG overproduction due to obesity. Thus, a moderate defect in catabolism of plasma TG appears to be responsible for one familial form of primary hypertriglyceridemia.
D000328:Adult; D001053:Apolipoproteins / Q000097:blood; D001692:Biological Transport; D005951:Glucose Tolerance Test; D006801:Humans; D006953:Hyperlipoproteinemia Type IV / Q000097:blood* / Q000235:genetics; D007328:Insulin / Q000097:blood; D007700:Kinetics; D008055:Lipids / Q000097:blood; D008074:Lipoproteins / Q000097:blood; D008079:Lipoproteins, VLDL / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D014280:Triglycerides / Q000097:blood*
D001053:Apolipoproteins; D007328:Insulin; D008055:Lipids; D008074:Lipoproteins; D008079:Lipoproteins, VLDL; D014280:Triglycerides; C030106:very low density lipoprotein triglyceride