title: Changes in cyclic nucleotide levels and phosphodiesterase and protein kinase activities in mitogenically stimulated 3T3 fibroblasts.
abstract: Activities of cyclic-nucleotide-hydrolysing enzymes cAMP-, cCMP- and cGMP phosphodiesterase, the intracellular concentrations of cAMP, cCMP, and cGMP, and the activity of the cAMP-dependent protein kinase were studied in serum-starved 3T3 cells stimulated to proliferate by serum. Within 1 and 2 min after stimulation the activities of cAMP- and cGMP phosphodiesterase were unaffected while the concentration of cGMP was raised and that of cAMP lowered, suggesting increased synthesis of cGMP and simultaneously reduced synthesis of cAMP. 48 h after stimulation, when the cells multiplied rapidly, both the cAMP phosphodiesterase and the cCMP phosphodiesterase were reduced. Evidence was also obtained that cAMP-dependent protein kinase is important for expressing the cAMP effect in the 3T3 cells.
mesh_terms: D000818:Animals; D002417:Cattle; D000242:Cyclic AMP / Q000032:analysis; D003563:Cyclic CMP / Q000032:analysis; D006152:Cyclic GMP / Q000032:analysis; D005347:Fibroblasts / Q000032:analysis / Q000187:drug effects* / Q000201:enzymology; D008934:Mitogens / Q000494:pharmacology*; D009712:Nucleotides, Cyclic / Q000032:analysis*; D010727:Phosphoric Diester Hydrolases / Q000032:analysis*; D011494:Protein Kinases / Q000032:analysis*; D013997:Time Factors
chemical_list: D008934:Mitogens; D009712:Nucleotides, Cyclic; D003563:Cyclic CMP; D000242:Cyclic AMP; D011494:Protein Kinases; D010727:Phosphoric Diester Hydrolases; D006152:Cyclic GMP