INCREASED HEPATIC SYNTHESIS AND ACCUMULATION OF PLASMA APOLIPOPROTEINB100 IN COPPER-DEFICIENT RATS DOES NOT RESULT FROM MODIFICATION IN APOLIPOPROTEIN-B MESSENGER-RNA EDITING

Experimentally induced copper deficiency in the rat results in increas ed plasma apolipoprotein B100 (ape B100) concentration in association with increased hepatic apo B100 synthesis. This enhancement of apo B10 0 synthesis and plasma accumulation accounts for the rise of plasma lo w density lipoprotein in these animals. In the present study, we have investigated if the selective increase in hepatic apo B100 synthesis i s accounted for by changes in apo B mRNA editing. Reverse transcriptio n coupled with polymerase chain reaction amplification and primer exte nsion analysis of apo B cDNA revealed no differences in apo B mRNA edi ting in either the liver or small intestine between control and copper -deficient rats. We speculate that the increase in apo B100 synthesis in the liver of copper-deficient rats reflects posttranslational alter ations in gene expression accompanying changes in very low density lip oprotein assembly and secretion.