title: Metabolism and pharmacokinetics of cinobufagin.
abstract: 1. The metabolic fate of cinobufagin, a major component of the cardiotonic Senso, has been studied after i.v. administration to rats. Two metabolites were detected in rat serum and shown by n.m.r. and mass spectroscopy to be desacetylcinobufagin (I) and 3-epidesacetylcinobufagin (II). 2. Inhibitory activities of I and II on guinea-pig heart Na+/K+-ATPase were less than that of cinobufagin. 3. Serum or plasma levels of cinobufagin, I and II in rats, cats and dogs were determined by h.p.l.c. after i.v. and/or oral administration of cinobufagin. After i.v. administration, cinobufagin, I and II appeared in rat serum, but in dog and cat plasma only unchanged cinobufagin was present. After oral administration, only II was detected in rat serum, but neither cinobufagin nor either of its metabolites (I and II) were found in cat and dog serum.
authors.affiliation: Research Laboratory, Kyushin Pharmaceutical Co., Ltd, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Toma
authors.forename: S
authors.initials: S
authors.lastname: Morishita
authors.forename: K
authors.initials: K
authors.lastname: Kuronuma
authors.forename: Y
authors.initials: Y
authors.lastname: Mishima
authors.forename: Y
authors.initials: Y
authors.lastname: Hirai
authors.forename: M
authors.initials: M
authors.lastname: Kawakami
mesh_terms: D000818:Animals; D001711:Biotransformation; D002018:Bufanolides / Q000378:metabolism* / Q000493:pharmacokinetics; D002415:Cats; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D004285:Dogs; D005260:Female; D006168:Guinea Pigs; D007275:Injections, Intravenous; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D013058:Mass Spectrometry; D009206:Myocardium / Q000201:enzymology; D051381:Rats; D011919:Rats, Inbred Strains; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013045:Species Specificity
chemical_list: D002018:Bufanolides; D000254:Sodium-Potassium-Exchanging ATPase; C002471:cinobufagin