Alterations in apolipoprotein B-48 in the postprandial state in NIDDM.
The intestine is a major site of cholesterol synthesis and produces apolipoprotein B-48, which is critical for intestinal cholesterol absorption and secretion. The purpose of this study was to examine postprandial changes in apolipoprotein B-48 in diabetes. Six non-insulin-dependent diabetic patients and six non-diabetic control subjects were given a high-fat meal (1300 kcal) and blood samples were taken pre- and postprandially, from which the triglyceride-rich lipoprotein fraction was isolated by ultracentrifugation (density < 1.006 g/ml). Apolipoprotein B-48 was separated on 4-15% gradient gels and quantified as a percentage of the fasting concentration by densitometric scanning. Total protein, triglyceride and cholesterol in the triglyceride-rich lipoprotein fraction, blood glucose, and serum insulin were also measured. Diabetic patients exhibited a postprandial triglyceride-rich apolipoprotein B-48 profile significantly different from that of control subjects (p < 0.05). The triglyceride and total protein concentration in the triglyceride-rich lipoprotein fraction mirrored the post-prandial profile and apolipoprotein B-48 in both groups. Significantly different patterns for triglyceride (p < 0.02) and total protein (p < 0.05) following the fat-rich meal were observed in the two groups. Fasting and postprandial triglyceride-rich lipoprotein cholesterol and total apolipoprotein B were significantly higher in diabetic patients than in control subjects (p < 0.05). Since apolipoprotein B-48 is the structural protein of intestinally-derived lipoprotein particles, these studies suggest an abnormality in intestinal lipoprotein metabolism in diabetes.
Curtin
A
A
Department of Biochemistry, Royal College of Surgeons in Ireland, Dublin.
Deegan
P
P
Owens
D
D
Collins
P
P
Johnson
A
A
Tomkin
G H
GH
D053283:Apolipoprotein B-48; D001055:Apolipoproteins B / Q000097:blood*; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D002784:Cholesterol / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000503:physiopathology; D004435:Eating; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008875:Middle Aged; D011897:Random Allocation; D012016:Reference Values; D013997:Time Factors; D014280:Triglycerides / Q000097:blood
D053283:Apolipoprotein B-48; D001055:Apolipoproteins B; D001786:Blood Glucose; D002784:Cholesterol; D006442:Glycated Hemoglobin; D014280:Triglycerides