| Abstrakt: |
Guanosine 3',5'-monophosphate (cyclic GMP) increased the rate of adenosine 3',5'-monophosphate (cyclic AMP) hydrolysis by phosphodiesterase preparations from several tissues. Stimulation of cyclic AMP hydrolysis occurred with initial concentrations of cyclic GMP as low as 0.08 µmand was seen with particulate phosphodiesterase preparations from rat liver, brain, kidney, heart, and thymus and with soluble preparations from liver and thymus. Higher concentrations of cyclic GMP (> 50 µm) were inhibitory to cyclic AMP hydrolysis in rat liver extracts. Inosine 3',5'-monophosphate (cyclic IMP) also stimulated the hydrolysis of cyclic AMP but was somewhat less effective than cyclic GMP. 5'-GMP,5'-IMP, uridine 3',5'-monophosphate, thymidine 3',5'-monophosphate, and guanosine had no effect. Cyclic AMP and cyclic IMP inhibited the hydrolysis of cyclic GMP by liver supernatant fractions. |
