Cyclic AMP and cyclic GMP as the respective mediators of the intracycle stimulation of DNA synthesis and mitosis induced by glucagon and insulin in primary neonatal rat hepatocytes

Abstract Within a wide range of concentrations ( i.e. , from 10 −15 to 10 −8 mole/1), equimolar mixtures of dibutyryl-cyclic AMP and dibutyryl-cyclic GMP or of glucagon and dibutyryl-cyclic GMP or of insulin and dibutyryl-cyclic AMP faithfully mimicked the stimulation of DNA-synthetic and mitotic activities elicited by equimolar associations of glucagon and insulin in 4-to-5-day-old neonatal rat hepatocytes in primary tissue culture. These observations strongly suggest that the intracycle, growth-promoting effects of the two pancreatic hormones are mediated via both purine cyclic nucleotides in the neonatal rat hepatocytes.