THE INFLUENCE OF CHELATION ON RADIOMANGANESE EXCRETION IN MAN AND MOUSE 1

Abstract

Following intravenous injection of Mn52 or Mn56 in humans and in mice, 95% or more of the dose was excreted in the feces. Three groups of 4 mice each gave excretion curves which could be analyzed graphically as the sum of 2 exponential functions, labelled the fast and slow components, respectively. Increasing the total dose of Mn, or pre-chelating it with ethylenediamine-tetraacetate, shifted a large proportion of the excreted Mn from the slow component into the fast component. It was suggested that the slow component represents physiologically bound Mn, and that with saturation of the binding sites with larger doses of Mn, the excess is spilled in the fast component. Likewise, the chelating agent competes with the physiological mechanism for the available Mn, and it is suggested that the degree of influence exerted by the chelating agent is inversely proportional to the strength of the physiological binding mechanism.