Frog rod outer segments freshly detached from dark-adapted retinas contain approximately
1-2 molecules of guanosine 3', 5'-cyclic monophosphate (cyclic GMP) for every 100 …

The concentration of guanosine 3', 5'-cyclic monophosphate (cyclic GMP) has been
examined in suspensions of freshly isolated frog rod outer segments using conditions which …

In the presence of 10 (-9) M calcium, rod outer segments freshly detached from dark-
adapted frog retinas contain between 0.01 and 0.02 moles of guanosine 3', 5'-cyclic …

1. The diffusion of sodium, potassium and rubidium (not chloride) ions across the disk
membrane is increased by cyclic guanosine monophosphate (cyclic GMP). 2. The increase …

Frog rod outer segments contain approximately 0.25 mol of GTP and 0.25 mol of ATP per
mol of rhodopsin 3 min after their isolation from the retina. UTP and CTP are present at 10 …

In isolated, intact frog retinae high concentrations of cyclic 3′, 5′-guanosine
monophosphate were found. These levels decline rapidly upon flash-illumination. A …

Although there is good agreement that light reduces the amount of cyclic GMP (cGMP) in the
retina, the exact time-course of this decrease is not well established. Bullfrog retinal sections …

The light-activated guanosine 3', 5'-cyclic monophosphate (cyclic GMP) phosphodiesterase
(PDE) of frog photoreceptor membranes has been assayed by measuring the evolution of …

Summary Cyclic GMP, GTP, and GDP were measured in outer segments of dark-adapted
frog retina, and following exposure to 2 min and 2 hr of light. GTP concentrations decreased …

We have measured the levels of 3', 5'-guanosine monophosphate (cyclic GMP) in isolated
retinas from toad to investigate their correlation to the opening and closing of the light …