Slower removal of intestinal apolipoprotein B-48 than of apolipoprotein B-100 in severely hypertriglyceridemic subjects.
Apolipoprotein B, the major structural protein of triacylglycerol-rich lipoprotein, occurs in two immunologically distinct forms, termed apolipoproteins B-100 and B-48. In man, the former is associated with triacylglycerol-rich lipoproteins of hepatic origin and the latter with intestinal triacylglycerol-rich lipoproteins. We have studied the rates of removal of the two proteins when 125I-labelled triacylglycerol-rich lipoproteins were reinjected into six severely hypertriglyceridemic subjects showing hyperchylomicronemia, and into two normal subjects. The specific radioactivities of apolipoproteins B-100 and B-48 were determined over periods of up to 30 h. In all six hyperlipemic subjects the removal of apolipoprotein B-100 was either significantly faster than that of apolipoprotein B-48 (in four) or similar in the two who cleared triacylglycerol-rich lipoproteins very slowly. When triacylglycerol-rich lipoproteins from two hyperlipemic subjects (in whom apolipoprotein B-48 was cleared more slowly) were injected into two normal subjects both B apolipoproteins were cleared at similar rates. Since apolipoprotein B-48 appears to be a marker for remnants of intestinal particles, its slower removal than that of apolipoprotein B-100 in severe hypertriglyceridemia suggests that one metabolic defect associated with the hyperchylomicronemia is defective removal of chylomicron remnants.
D000328:Adult; D053299:Apolipoprotein B-100; D053283:Apolipoprotein B-48; D001053:Apolipoproteins / Q000378:metabolism*; D001055:Apolipoproteins B; D005260:Female; D006801:Humans; D006949:Hyperlipidemias / Q000378:metabolism*; D006953:Hyperlipoproteinemia Type IV / Q000378:metabolism; D007408:Intestinal Absorption; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D014280:Triglycerides / Q000097:blood*
D053299:Apolipoprotein B-100; D053283:Apolipoprotein B-48; D001053:Apolipoproteins; D001055:Apolipoproteins B; D014280:Triglycerides