Hepatic fatty acid-binding protein mRNA is regulated by growth hormone

Hepatic fatty acid-binding protein (FABP) is one of several abundant proteins which may participate in fatty acid uptake and utilization. Using differential hybridization to screen for growth hormone-responsive gene products, a complementary deoxyribonucleic acid (cDNA) was isolated which proved to be a hepatic FABP cDNA fragment. Hypophysectomy caused a 60% reduction in hepatic FABP messenger ribonucleic acid (mRNA) levels in rat liver, and growth hormone administration to hypophysectomized rats resulted in restoration of the expression of hepatic FABP mRNA. Other pituitary hormones did not alter these changes in expression. The response to growth hormone occurred within 4 hours of administration. During development, expression of hepatic FABP mRNA in rat liver was low in late fetal life, with increases to 40% of adult values by day 2 of life. Significant increases to adult levels did not occur until after day 25, when weaning is essentially completed. Alteration of hepatic FABP mRNA expression by growth hormone in rat liver may be important in the complex regulation of fatty acid uptake and metabolism.