Identification of turkey biliary metabolites of ractopamine hydrochloride and the metabolism and distribution of synthetic [14C]ractopamine glucuronides in the turkey.
1. The bile duct cannulated turkey poult (n = 3) dosed orally with [14C]ractopamine HCl [(1R*,3R*),(1R*,3S*)-4-hydroxy-alpha-[[[3-(4-hydroxy[14C]phenyl)-1-methy lpropyl]amino]methyl]-benzenemethanol hydrochloride; 19.9 mg; 9.28 microCi] excreted 37.4 +/- 12.1% (mean +/- SD) of the administered radioactivity in bile by 24 h post-dosing. 2. A mono-glucuronide, conjugated at C-10 (the methylpropylamino phenol) of ractopamine, accounted for 76.6% of biliary radioactivity. 3. Urine collected from the colostomized turkey poult (n = 3) orally dosed with synthetic [14C]ractopamine-glucuronides (10.1 mg; 3.6 microCi) contained 11.9 +/- 1.0% (mean +/- SD) of the administered radioactivity 24 h after dosing, indicating that some absorption of radioactivity occurred. Faeces contained 60.6% of the administered radioactivity and carcasses (with gastrointestinal tracts) contained 23.3% of the starting radioactivity. 4. Five colostomized poults were fitted with bile duct cannulas and were dosed intraduodenally with 10.2 mg (3.6 microCi) synthetic [14C]ractopamine-glucuronides. Urine and bile contained 15.5 +/- 2.2 and 16.8 +/- 2.1% respectively of the administered radiocarbon by 24 h post-dosing. Faeces contained 54.3% of the administered radioactivity. Total absorption of the dosed radioactivity averaged 33.4%. 5. Bile and urine collected from the colostomized, bile-duct cannulated bird contained mainly ractopamine glucuronides. Indirect evidence suggests that the dosed ractopamine glucuronides were not absorbed intact.
Smith
D J
DJ
US Department of Agriculture, Agricultural Research Service, Biosciences Research Laboratory, Fargo, ND 58105-5674, USA. smithd@fargo.ars.usda.gov
Feil
V J
VJ
Paulson
G D
GD
D000318:Adrenergic beta-Agonists / Q000008:administration & dosage / Q000652:urine*; D000818:Animals; D001646:Bile / Q000378:metabolism*; D002250:Carbon Radioisotopes; D006133:Growth Substances / Q000378:metabolism; D010627:Phenethylamines / Q000008:administration & dosage / Q000652:urine*; D014422:Turkeys / Q000378:metabolism*
D000318:Adrenergic beta-Agonists; D002250:Carbon Radioisotopes; D006133:Growth Substances; D010627:Phenethylamines; C060897:ractopamine