Excretion and Body Distribution of Promethium 147

Abstract

Rats were injected intramuscularly with 1 microcurie of promethium chloride Pm 147. Distribution of the isotope in body tissue and relative rate of excretion in urine and feces were different from previously reported studies in which the isotope was administered intravenously. The major route of isotope excretion both in rats given a diet and those fasted was via the intestinal tract, with the largest amount being excreted the second day after injection. Urinary excretion of the isotope was greatest during the first 24 hours after injection and then declined markedly in subsequent days in both fed and fasted rats. Within 24 hours, the liver showed the highest activity (20% of the administered dose) as compared to blood, kidney, and bone. Activity of the isotope in injected muscle for the first three days was greater than in noninjected muscle.