UPTAKE, DISPOSITION, AND PERSISTENCE OF ACRYLONITRILE IN RAINBOW-TROUT

The uptake and disposition of [2,3-C-14]acrylonitrile-derived C-14 were studied in rainbow trout by water exposure. Trout were exposed to [C-14]ACN at 5.3 mu g/liter and sampled at various times during a 24-hr uptake phase. After transfer to fresh water, fish were sampled to 72 hr for the estimation of elimination rates and the half-life of C-14. Throughout these experiments several fish were also sacrificed for whole-body autoradiography. The uptake of C-14 in carcass and viscera began to level off at 24 hr and the apparent bioconcentration factor was low and of the order of 3-4. In the elimination studies, the C-14 appeared to persist in both muscle and visceral tissue for a longer time than anticipated based upon its octanol-water partition coefficient (log p = -0.92). The t(1/2) of C-14 in muscle in two such experiments was calculated to be 117 and 102 hr. The autoradiographs of whole-body sections of exposed trout also revealed a slow loss of C-14 from muscle. Muscle extracts prepared from exposed fish were essentially nondialyzable. When dialyzed muscle extract was analyzed for protein and C-14 after SDS-PAGE electrophoresis, most of the C-14 was associated with a single protein band with a mobility comparable to standards in the 10,000 Dalton range. These studies indicate that the long half-life of C-14 seen in trout muscle may be due to covalent binding of C-14 to a protein with a molecular weight of approximately 10,000 Daltons. (C) 1995 society of Toxicology