title: Metabolism of isoprenaline in dog and man.
abstract: 1. The metabolism of isoprenaline has been studied in man and dog following intravenous and oral or intra-duodenal administration.2. Intravenous isoprenaline was excreted largely unchanged in urine in both species. Only one-third of the radioactivity in urine was in the form of the O-methyl metabolite.3. After oral doses in man or intraduodenal doses in dogs, plasma radioactivity was almost entirely as conjugated isoprenaline and this metabolite accounted for more than 80% of radioactivity in urine.4. Catechol-O-methyl transferase may be less important than Uptake(2) in limiting the pharmacological action of isoprenaline.5. Pharmacological response (heart-rate increase) was related to plasma concentration of isoprenaline only after rapid intravenous injections. In dogs, following prolonged infusion or intraduodenal doses, heart rate returned to base-line values when plasma concentrations of isoprenaline were high.
mesh_terms: D000284:Administration, Oral; D000818:Animals; D002394:Catechol O-Methyltransferase / Q000378:metabolism; D004285:Dogs; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007275:Injections, Intravenous; D007545:Isoproterenol / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology / Q000652:urine; D008297:Male; D008875:Middle Aged; D013045:Species Specificity; D013997:Time Factors; D014316:Tritium
chemical_list: D014316:Tritium; D002394:Catechol O-Methyltransferase; D007545:Isoproterenol