Low-density lipoprotein apolipoprotein B production differs between laboratory opossums exhibiting high and low lipemic responses to dietary cholesterol and fat.

Two partially inbred strains of laboratory opossums exhibit extremely high or low levels of low-density lipoprotein (LDL) cholesterol concentrations, respectively, when challenged with a high-cholesterol and high-fat (HCHF) diet. The present studies were conducted to determine whether the catabolism or the production of LDL apolipoprotein B (apoB) is responsible for the variability in plasma LDL cholesterol and apoB concentrations. Iodinated LDL prepared from plasma of donor opossums consuming HCHF diet was injected into high- and low-responding recipients maintained on the HCHF diet.

Expression levels of ACAT1 and ACAT2 genes in the liver and intestine of baboons with high and low lipemic responses to dietary lipids.

Acyl-coenzyme A:cholesterol acyltransferase (ACAT) 1 and ACAT2 play an important role in cellular cholesterol esterification and thus modulate intestinal cholesterol absorption and hepatic lipoprotein secretion. The relative expression levels of ACAT1 and ACAT2 in human tissues differ from those in other animals, including nonhuman primates. The present study compared the relative expression levels of ACAT1 and ACAT2 in baboons with high and low lipemic responses to dietary lipids.

Cholesterol absorption and hepatic acyl-coenzyme A:cholesterol acyltransferase activity play major roles in lipemic response to dietary cholesterol and fat in laboratory opossums.

Partially inbred lines of laboratory opossums differ considerably in their low-density lipoprotein (LDL) cholesterol responses to dietary cholesterol and fat. Genetic analysis suggested that a single major gene is responsible for the variation in LDL cholesterol on the high cholesterol and high fat (HCHF) diet. We measured cholesterol absorption and acyl-coenzyme A:cholesterol acyltransferase (ACAT) activity in intestine and liver to narrow the search for the major gene.