Journal of Lipid Research, Vol 32, 1133-1141, Copyright © 1991 by Lipid Research, Inc.
Abnormal clearance of postprandial Sf 100-400 plasma lipoproteins in insulin-dependent diabetes mellitus
A Georgopoulos and RD Phair
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205.
Studies were carried out in three normolipidemic non-obese men with
insulin-dependent diabetes mellitus (IDDM) and three normal men, to assess
whether the clearance of postprandial Sf 100-400 lipoproteins is decreased
in IDDM. Sf greater than 100 lipoproteins isolated from plasma 4.5 h after
fat ingestion were labeled with 125I and injected into the same subject
intravenously. ApoB radioactivity was measured over time in Sf greater than
400, Sf 100-400, and Sf 20-100 lipoproteins isolated from plasma and
analyzed using a kinetic model that included both fast and slow
delipidation cascades, where lipolysis and uptake of particles by the liver
and other tissues were represented. Fractional catabolic rates of Sf
100-400 lipoproteins (min- 1) were decreased in diabetic versus control
subjects: fast = 0.170 +/- 0.126 versus 0.680 +/- 0.242 (mean +/- SD) (P
less than 0.05, two- tailed) and slow = 0.011 +/- 0.006 versus 0.031 +/-
0.015 (P less than 0.05, one-tailed). Kinetic analysis showed that the data
were consistent with decreased uptake by the tissues for the fast cascade
(diabetic, 0.084 +/- 0.082, vs. control, 0.617 +/- 0.328, P less than 0.05,
one-tailed). A similar trend was observed for the slow cascade. There were
no significant differences between the two groups in the intraplasma
lipolysis rates of Sf 100-400 particles. Analysis of the composition of the
injected particles showed that they were total cholesterol (TC)- versus
triglyceride (TG)-enriched (P less than 0.001, log-ratio analysis of
composition) in IDDM subjects.(ABSTRACT TRUNCATED AT 250 WORDS)