Pretranslational Regulation of alpha sub(2u)-Globulin in Rat Liver by Growth Hormone

Hypophysectomy is known to cause complete suppression of the hepatic synthesis alpha sub(2u)-globulin. The effect of hypophysectomy on the synthesis of alpha sub(2u)-globulin can be reversed by multiple hormone treatment. The role of pituitary growth hormone in the multihormonal regulation of alpha sub(2u)-globulin in rat liver was examined in the hypophysectomized male rats with and without growth hormone supplementation. The possible effect of growth hormone on the translation of the mRNA for alpha sub(2u)-globulin was examined with cultured hepatocytes derived from growth hormone-deficient rats. Culture of these cells in the presence of growth hormone for 24 h did not turn on the synthesis of alpha sub(2u)-globulin. These results indicate that growth hormone regulates the synthesis of alpha sub(2u)-globulin by acting at a step antecedent to mRNA translation.