title: Cyclic GMP efflux from liver slices.
abstract: Cyclic GMP efflux from liver slices was studied when the intracellular cyclic GMP levels were elevated by incubation with N-methyl-N'-nitro-N-nitrosoguanidine (0.1 mM) and 3-isobutyl-1-methylxanthine (0.25 mM). A probenecid-sensitive and a probenecid-insensitive efflux system for cyclic GMP was found. It is suggested that the former system operates a carrier, which is saturable, the capacity of which is increased by alkylation with N-ethylmaleimide. The rate of net efflux of cyclic GMP increases 20-fold in the temperature interval 18-37 degrees C. Probenecid (0.5 mM) gives 50% inhibition of this system. The probenecid-insensitive cyclic GMP efflux component probably corresponds to passive diffusion. It appears that efflux may be an important complement to cyclic 3':5'-nucleotide phosphodiesterase activity in reducing intracellular cyclic GMP levels.
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology*; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D006152:Cyclic GMP / Q000378:metabolism*; D066298:In Vitro Techniques; D007460:Iodoacetamide / Q000494:pharmacology; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology*; D011339:Probenecid / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013806:Theophylline / Q000031:analogs & derivatives*
chemical_list: D008769:Methylnitronitrosoguanidine; D000001:Calcimycin; D013806:Theophylline; D006152:Cyclic GMP; D011339:Probenecid; D002118:Calcium; D015056:1-Methyl-3-isobutylxanthine; D007460:Iodoacetamide