Characterization of serum lipoproteins from Suncus: a candidate animal model for abetalipoproteinemia.

We have previously reported that fatty liver was induced in a novel experimental animal, Suncus murinus (suncus), by 24-h fasting and that apolipoprotein B (apo B) was not actively synthesized in the liver. However, a faint signal of apo B mRNA was detected in the liver, suggesting possible synthesis of apo B. Small amounts of VLDL and LDL have been separated from suncus serum by ultracentrifugation. Electron microscopic study of the lipoproteins revealed the existence of small particles in VLDL. High performance liquid chromatographic analysis of the lipoproteins showed that the peaks of TG and cholesterol were mainly at the HDL fraction. These results indicate the existence of lipoproteins as small as HDL which were rich in TG and floated at the density of VLDL upon ultracentrifugation. Apolipoprotein analysis showed two bands of 500- and 200-kDa proteins in VLDL and LDL. Western blot analysis using antibody against the 500-kDa protein revealed reaction not only with suncus 500- and 200-kDa proteins but also with human apo B-100. In conclusion, a small amount of apo B is transported in the suncus serum as VLDL and LDL, although almost all lipid is packed in HDL-size particles.