Change of ribonuclease H activity in developing and regenerating rat liver.

Ribonuclease H (RNAase H), which specifically degrades RNA in RNA-DNA hybrids, has been studied with proliferating normal liver. Partial hepatectomy results in approximately two-fold increase of RNAase H activity in 24 h after 16 h lag phase in liver after operation. The activity of RNAase H as well as DNA ligase in the liver of newborn rats is high and the activities of both enzymes gradually decrease with same ratio during differentiation to low levels in the adult.