Role of Hypotension in the Initial Response of X-Irradiated Chicks

Abstract

In young chicks, a severe hypotension developed during the initial post-irradiation period after exposure to 1000 r X-ray at 43 r/minute. Birds that failed to survive the first 24 hours showed a small drop in blood pressure soon after exposure and a more drastic fall during the last half of the survival period. The early hypotension was not associated with any significant renal dysfunction, but complete anuria was seen as more severe hypotension developed. Shielding the kidney region during irradiation prevented direct damage to the kidneys, but did not prevent either severe hypotension or renal failure. On the other hand, local irradiation of the kidney region produced no effect on blood pressure, but frequently produced sufficient direct renal injury to result in a fatal uricemia. Effects of sustained hypotension produced by controlled hemorrhage indicated that the low arterial pressure during the last half of the postirradiation survival period was insufficient to maintain normal renal function.