Journal of Lipid Research, Vol 25, 1072-1083, Copyright © 1984 by Lipid Research, Inc.
Serum lipids and lipoprotein composition in spontaneously diabetic BB Wistar rats
ST Patel, HA Newman, AJ Yates, P Thibert and JM Falko
Serum lipid and lipoprotein composition in spontaneously diabetic BB Wistar
rats, nondiabetic littermates, and control Wistar rats was studied to
elucidate diabetes-related abnormalities of lipoprotein composition. Serum
total triglycerides and pre-beta-lipoprotein concentrations of
insulin-treated spontaneously diabetic BB and nondiabetic littermate rats
were significantly higher than those of control Wistar rats. Serum
cholesterol and HDL cholesterol concentrations of spontaneously diabetic BB
and nondiabetic littermate rats did not differ from controls.
Concentrations of very low density lipoproteins (VLDL), low density
lipoproteins (LDL), and high density lipoproteins (HDL) of spontaneously
diabetic BB and nondiabetic littermate rats were higher than those of
normal rats. With sodium dodecylsulfate-polyacrylamide gel electrophoresis
it was observed that the spontaneously diabetic BB and nondiabetic
littermate rat VLDL contained higher percentages of apoE relative to total
apoC when compared with control Wistar rats. With isoelectric focusing,
apoC-II relative percentages in VLDL and HDL of both spontaneously diabetic
BB and nondiabetic littermate rats were higher than apoC-II proportions in
VLDL and HDL of controls. Apolipoprotein A-I of the control rat HDL showed
four isoforms that focused at pI 5.8 (17.3%), 5.75 (30.6%), 5.65 (31.8%),
and 5.55 (20.5%); however, the spontaneously diabetic BB and nondiabetic
littermate rat HDL apoA-I was mainly represented by two isoforms that
focused at pI 5.8 and 5.75. VLDL of both diabetic and nondiabetic BB rats
contained higher levels of acidic apoE isoforms compared to their
counterparts in control Wistar rats. Although HDL cholesterol
concentrations of spontaneously diabetic BB rats remained normal, protein
concentrations were higher resulting in a low cholesterol/protein ratio in
HDL suggesting that the cholesterol- carrying capacity of spontaneously
diabetic BB rat HDL could be less than normal and may be due to an abnormal
apoA-I composition. Quantitative alterations of lipid and lipoprotein
composition appear in the BB Wistar rat when compared to the Wistar rat,
but some of the changes are more pronounced in the spontaneously diabetic
BB Wistar rat.