Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P20020 (adenosine triphosphatase)
 3,299 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the course of study of the metabolic fate of "Kyushin", a traditional medicine containing toad venom, the metabolic fates of bufalin and cinobufagin, main constituents of toad venom, have been studied. Six metabolites were detected in the extracts from incubation mixture of rat liver slice with bufalin, and one main metabolite shown by mass spectroscopy and high performance liquid chromatography (HPLC) to be 3 alpha-bufalin. Serum levels of bufalin and 3 alpha-bufalin were determined by HPLC after oral administration of 2000 micrograms/kg of bufalin, and both compounds appeared in the rat serum. On the other hand, only 3 alpha-bufalin appeared after administration of 20 or 200 micrograms/kg. 3 alpha-Bufalin levels increased dose dependently. Serum levels of cinobufagin and its metabolites and digitoxin were compared after repeated intravenous administration (5 h interval) of cinobufagin or digitoxin. Although digitoxin was accumulated in the rat serum, cinobufagin and its metabolites were not. Inhibitory activities of metabolites of bufalin and cinobufagin on (Na+ + K+)-adenosine triphosphatase were less than those of original compounds.
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PMID:[Metabolic fate of bufalin and cinobufagin]. 166 63

1. We have reported that the bufadienolide, bufalin (purified from toad skin), was more potent than ouabain in inhibiting the sodium/potassium-dependent adenosine triphosphatase from canine kidney (Sigma) [Brownlee, A.A., Lee, G. & Mills, I.H.J. Physiol. (London) 1987; 390, 94P]. 2. The activities of bufalin and cinobufotalin were compared with ouabain in the [3H]ouabain binding assay and on 86Rb uptake in human erythrocytes. 3. When the percentage binding of ouabain-sensitive [3H]ouabain was plotted against the log of the concentration of drug in mol/l, it was shown that the bufalin curve was shifted to the left of that of ouabain and that of cinobufotalin was to the right. 4. Linear regression lines were fitted to the data transformed as the log of (p/1--p) plotted against the log of the drug concentration, where p is the proportion of maximal ouabain-sensitive activity at the drug concentration being considered. The IC50 (the concentration of drug producing a 50% change in the maximal ouabain-sensitive response) was 1.4 x 10(-9) mol/l for bufalin, 9.7 x 10(-9) mol/l for ouabain and 1.70 x 10(-7) mol/l for cinobufotalin. 5. The introduction of bufalin 1 h before ouabain reduced the binding of [3H]ouabain to 23.4 +/- 1.5% (P less than 0.001). Bufalin added in the second hour reduced the ouabain-sensitive binding from 100 +/- 1.9% to 87.4 +/- 2.9% (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Actions of bufalin and cinobufotalin, two bufadienolides respectively more active and less active than ouabain, on ouabain binding and 86Rb uptake by human erythrocytes. 215 44