Regulation of sterol carrier protein-2 gene expression in rat liver and small intestine

Sterol carrier protein-2 (SCP2) is a peroxisomal protein most highly expressed in non-steroidogenic tissues such as liver and small intestine. We have examined SCP2 gene expression during development and after alterations in lipid and bile acid metabolism and compensatory cell growth in the rat. The developmental expression of SCP2 displayed a biphasic pattern of relative mRNA abundance with a peak at day 19 to 20 of fetal life, reaching adult levels by day 14 and after day 14 in small intestine. In adult rats there was no effect on SCP2 mRNA abundance, or the relative proportions of the four SCP2 transcripts after gemfibrozil treatment, 30-fold changes in hepatic cholesteryl ester and triglyceride levels, bile ligation, compensatory hepatic or renal growth. However, immunoblot analysis of tissue homogenates revealed that SCP2 protein is decreased by 75% in the livers of gemfibrozil-treated animals and increased by 5-fold at 48 h in regenerating liver and in the remaining kidney after unilateral nephrectomy. Taken together these results suggest that SCP2 gene expression is developmentally regulated and modulated translationally or post-translationally in the adult rat by gemfibrozil and compensatory cell growth.