Stretch stimulates cyclic nucleotide metabolism in the isolated frog ventricle

An investigation has been made of the effect of stretch on cyclic nucleotide metabolism. The levels of endogenous adenosine 3',5' - cyclic monophosphate (cyclic AMP) and guanosine 3',5' - cyclic monophosphate (cyclic GMP) were measured during different patterns of stretch and release. Stretch to Lmax produced a moderate increase in cyclic AMP and a proportionately greater increase in cyclic GMP; as a result, the ratio cyclic AMP: cyclic GMP fell to around 0.5 x control (unstretched) value. The effects of releasing previously stretched preparations resulted in a decrease in cyclic GMP levels. In contrast, the increase in cyclic AMP level following stretch was not affected by this procedure. Nevertheless, these effects together produced an increase in the ratio cyclic AMP: cyclic GMP, the magnitude of which increased linearly with the amplitude of release.