ABSTRACT
This chapter describes the molecular mechanism of induction of the L-type Pyruvate kinase (PK) by insulin and dietary fructose. The L-type PK mRNA level is markedly reduced in streptozotocin-induced diabetes in the liver of rats fed a high dextrose diet. Insulin administration to diabetic rats results in an increase in the level of the L-type PK mRNA in the liver. The chapter investigates the mechanisms of action of insulin and carbohydrates further using cultured hepatocytes based upon in vivo observations. The in vivo and in vitro studies suggest that the mechanism of transcriptional stimulation of the L-type PK gene by insulin or dietary fructose is very complicated. An important question is whether these cis- and trans-acting factors are involved in transcriptional stimulation of the L-type PK gene by insulin and dietary fructose. This problem could not be solved in the transfection system using cultured hepatocytes.
