title: Uptake and liberation of [3H]16-acetyl-gitoxin in the isolated guinea pig atrium.
abstract: In isolated, spontaneously beating guinea-pig atria the uptake, liberation and inotropic effect of [3H]16-acetyl-gitoxin were studied. At a concentration of 53.5 nmol/l 16-acetyl-gitoxin caused an increase in contractile force of 21% within 45 min. Within 60 min, 190.7 pmol per g tissue were taken up. The tissue-to-medium radioactivity ratio (T/M ratio) was 4.7. In the wash-out experiments, 40% of the accumulated radioactivity was liberated into the medium within 30 min, while the glycoside-dependent increment of inotropy ceased to continue. The kinetic properties of 16-acetyl-gitoxin were found to resemble more closely those of digitoxin than those of ouabain.
mesh_terms: D000113:Acetyldigoxins / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D004077:Digoxin / Q000031:analogs & derivatives*; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism*
chemical_list: D000113:Acetyldigoxins; C025972:16-acetylgitoxin; D004077:Digoxin