Expression of S14 protein gene in rat liver in response to partial hepatectomy, and its regulation with T 3 and sucrose

Abstract

In rat liver a significant decrease in the expression of the protein S14 gene was observed 4 h after partial hepatectomy compared to sham operation performed after overnight fasting. After 24 h a| decrease was recorded after partial hepatectomy or sham operation and this low level persisted for 120 h. A single i.p. dose of 3,5,3′- l.-triiodothyronine (10 μg/100 g body wt), a potent inducer of gene S14, reversed the inhibition of gene expression at each time interval studied in both the partially hepatectomized and sham-operated rats. Sucrose administration to rats 24 h after partial hepatectomy or to sham-operated rats restored the induction of hepatic mRNA S14 gene expression in approx. 60% of controls as recorded after 4 and 24 h. These data suggest that the expression of gene S14 was altered in the liver after partial hepatectomy or sham operation by food restriction, and no compensatory effect of the increased lipid metabolism was found in rat remnant liver. Our findings indicate that thyroid hormone and sucrose administration exert similar effects on hepatic expression of the protein S14 gene both in the regenerating liver and in the intact liver of sham-operated animals. In spite of the increased lipid metabolism of the liver after resection, the sensitivity of mRNA S14 expression to triiodothyronine and sucrose was unchanged and its regulation was operative in a| positive manner. These results also suggest that the treatment of a| regenerating liver containing both the parent and the daughter hepatocytes with sucrose and/or triiodothyronine resulted in a| fully restored response.