Effect of Radioprotective Sulphydryl Compounds on the Oxygen Tension in the Spleen of Mice

IN a previous paper 1 the mechanism of the radioprotective action of the biologically active amines histamine, epinephrine, tryptamine and β-phenylethylamine was investigated. In studying the effect of these compounds on the oxygen tension in the spleen and bone marrow of unanæsthetized mice strong evidence was obtained that a relation exists between the percentage protection against a lethal dose of X-rays afforded by these compounds and the degree of hypoxia caused in the blood-forming organs. Furthermore, it was shown 2 that cyanide also causes hypoxia in the spleen as a consequence of vasoconstriction and that this effect may well explain its protective action in mice.