Presence and Identity of Vasotropic Substances in Blood of Rats Subjected to Acute Whole Body Roentgen Ray Irradiation

Abstract

A systematic study has been made of the effect of 600 r acute whole and regional roentgen ray irradiation on the peripheral vascular system of the rat. The effects of such radiation upon the formed elements of the blood, the intestinal tract and other body tissues were correlated with the published data concerning radiation damage of these tissues. Peripheral vascular function is not impaired by a direct action of the radiation on the precapillary sphincters and terminal arterioles but is mediated through the release of a vasodepressor material by the liver. This material (VDM), which is present in the circulation during the first postirradiation week, has been shown to be the same as that which appears in the blood of animals in irreversible shock. It fits all of the criteria for ferritin. However, the sequence of its appearance is different from that reported for physiological shock states. A vaso-excitor material has been found in the blood of irradiated animals during the 2d postirradiation week. This material (VEM) fits the criteria established for the VEM found in the blood of animals in the reversible phase of shock.