Partial hepatectomy and/or surgical stress provoke changes in the expression of lipoprotein lipase and actin in liver and extrahepatic tissues

Abstract

The expression of lipoprotein lipase (LPL) and actin genes was examined in heart, muscle and white adipose tissue (WAT) and the expression of albumin and actin genes was examined in regenerating liver after 2/3 hepatectomy. Both surgical stress and partial hepatectomy (PH) affected LPL and actin mRNA levels in muscle and WAT, but not in heart. The changes in LPL mRNA suggest transcriptional regulation of the enzyme during hepatic regeneration. Our results show for the first time that the LPL gene expression in the different tissues studied is altered not only by the surgical stress, but also by PH per se. Actin expression is also affected in some tissues. In liver, PH and surgical stress altered the expression of albumin and total mRNA. The total mRNA of the other tissues studied did not change. The changes observed in LPL in different tissues, especially in WAT and muscle, may be responsible for some of the changes in lipidic metabolism, thus allowing for some plasma lipoproteins to be used as substrates by the LPL activity that arises in the liver during hepatic regeneration. The fatty acids derived from these lipoproteins would constitute not only an energy source but also the building material needed in the process of restoration of the lost hepatic mass. It is suggested that hormonal changes taking place after surgery are responsible for the variation in the levels of the different mRNAs studied.