Effects of phenoxybenzamine on early stages of liver regeneration in partially hepatectomized rats

Abstract

The changes in regenerating rat liver during the first 24 hr after 70 per cent hepatectomy have been studied using phenoxybenzamine, an adrenergic blocker. At 5 mg/kg, given before operation, the drug did not alter the increased uptake of 3H orotic acid into the acid-soluble intracellular fraction of the liver detected at 1 hr after hepatectomy, but the increase in 3H orotic acid incorporation into nuclear RNA at this time was only 40 per cent of that in untreated partially hepatectomized rats. Induction of ornithine decarboxylase (EC 4.1.1.17) was delayed by about 2 hr, but DNA synthesis was unaffected. When 5 mg/kg phenoxybenzamine was given between 5 and 10 hr after partial hepatectomy, DNA synthesis was altered. Given 9 hr after operation the drug delayed the onset of peak DNA synthesis by 3 hr, from 21.5 to 24.5 hr. The induction of nuclear histone phosphokinase was also delayed.