Whole-body retention and tissue distribution of 60Co in rats after oral administration of freshwater fish contaminated with 60Co.

The purpose of this report is to compare the whole-body retention and tissue distribution in rats of 60Co administered by gavage as inorganic 60CoCl2 or in a form incorporated into freshwater fish. Orizias latipes were placed in vessels containing 21. of tap water with radioactive cobalt. Periodically thereafter the fish were sacrificed, homogenized, and administered to rats via a stomach tube. Control groups of rats were given the radionuclide alone or together with a homogenate of nonradioactive fish. The whole-body retention and tissue distribution of the radionuclide were determined with an Armac counter. The results revealed that rats gavaged with 60Co incorporated into the fish retained much more 60Co than control rats. This trend was notable in rats given fish kept in radioactive solution for longer periods. Marked differences in tissue distribution of 60Co were also observed between rats given 60Co incorporated into fish and control rats.