The role of receptor kinase in insulin action and the effects of insulin on human hepatoma cells

Insulin has both short- and long-term effects on cellular metabolism. The short-term effects are known to involve the insulin receptor, a protein kinase capable of phosphorylating itself and other proteins. The role of the receptor was elucidated by studies of a mutant insulin receptor which lacked kinase activity and inhibited several actions of insulin. The long-term effects of insulin could be demonstrated by its growth-promoting effect on hepatoma cells, and by the suppression in transfected hepatoma cells of hepatitis B virus antigen production in a dose-dependent manner. The process whereby insulin appears to regulate gene expression is not clearly understood.