109Cadmium Absorption, Excretion, and Tissue Distribution Following Single Tracer Oral and Intravenous Doses in Young Goats

Abstract

Cadmium metabolism was studied in six 2.5-month-old goats following a single oral or intravenous tracer dose of 109Cd. Whereas, more than 90% of the oral dose was excreted in the feces within five days after dosing, only 5.6% of the intravenous dose was excreted via feces during this time. Feces was the predominant route of excretion regardless of method of dosing. Following a peak level of endogenous excretion on the second day after intravenous dosing, there was a very sharp reduction ia rate of endogenous excretion so that 12 days after dosing endogenous excretion was only 7% of the peak. Fourteen days after intravenous dosing, highest concentrations were observed in the liver, kidney, and spleen, in descending order. In contrast, following oral dosing highest concentrations were found in the small intestine wall, kidney, and liver. A much higher level of 109Cd was found in the liver, heart, and spleen of intravenously dosed animals relative to other tissues than in orally dosed ones. It is theorized that intravenously administered cadmium is transported in a different form from that absorbed from the gastrointestinal tract and that this materially affects cadmium metabolism.