title: Effects of diamide on cyclic nucleotide levels in rat retina.
abstract: The concentrations of guanosine 3',5' monophosphate (cyclic GMP) and adenosine 3',5' monophosphate (cyclic AMP) were measured in rat retinas incubated under control conditions and in retinas incubated with diamide, a relatively specific glutathione oxidant. Retinas incubated with either glucose or pyruvate as the substrate for 30 min in the dark contained about 50 picomoles cyclic GMP/mg protein and 7 picomoles cyclic AMP/mg protein. Light-exposed control retinas contained about 70% less cyclic GMP (14.4 picomoles/mg protein) and 20% less cyclic AMP (5.4 picomoles/mg protein). Addition of diamide to the incubation medium at concentrations between 0.1 and 1.0 mM produced a concentration-dependent decrease in the dark level of cyclic GMP, but did not affect its concentration in the light or the concentration of cyclic AMP in dark-maintained and light-exposed retinas. The major effect of diamide was to reduce the normal dark-light difference in the concentration of cyclic GMP. Oxidizing conditions thus appear to alter selectively the light-sensitive compartment of retinal cyclic GMP.
mesh_terms: D000818:Animals; D001391:Azo Compounds / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism*; D003958:Diamide / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012160:Retina / Q000187:drug effects* / Q000378:metabolism
chemical_list: D001391:Azo Compounds; D003958:Diamide; D000242:Cyclic AMP; D006152:Cyclic GMP