Metabolism and route of excretion of the chloro-cyclodiene HCE in the pigeon.

Male feral pigeons were fitted with re-entrant bile duct cannulae, or were colostomized to facilitate the separate collection of urine and feces. After administration of 15 mg kg(-1) of [14C]-HCE by intraperitoneal injection, collections of bile and urine were made to determine the routes of excretion and the major metabolites. Within seven hrs the percentages of injected 14C excreted were 16.2 2.9% in the urine of colostomized birds and 12.8 1.1% in the bile of cannulated birds. Since the rate of elimination of 14 C in the feces of colostomized birds was very low (29% dose in 12 days) compared with 59% in urine, apparently some biliary metabolites were reabsorbed from the gut prior to elimination in urine. Nearly all excreted material was in conjugated form. Biliary conjugates were predominantly glucuronides (greater than 84% of total 14C) whereas 96% of the conjugated material in urine was sulfate. Initial metabolism was predominantly oxidative with the formation of a monohydroxy epoxide (HHC), which was subsequently converted into two secondary metabolites (endo-HHC and dihydroxy-HCE). In contrast to other species, no measurable quantity of trans-diol was formed. The same pattern of initial metabolism was found in hepatic microsomes. The metabolism and excretion of HCE is slower in the pigeon than in the male rat, thus providing further evidence for the limited capability of the species to perform certain detoxifying transformations.