MODIFICATION OF THE RADIATION-INDUCED INCREASE IN ADENOSINE TRIPHOSPHATASE ACTIVITY OF THE SPLEEN BY VARIOUS CHEMICAL AGENTS.
Rept. for 1 Dec 65-31 May 66.
CHICAGO UNIV ILL TOXICITY LAB
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A study was conducted on the influence of various chemical agents and biological preparations on the radiation-induced increase in adenosine triphosphatase activity of the spleen of rats using cobalt gamma radiation exposures. Exposure of rats to 21.2 r and 50 r per day over a 10-hour period caused dose-dependent increases in enzyme activity. Progressive increases occurred during the first few days followed by maintenace of the activity at a constant elevated level. Chemical agents were tested for protective activity by exposing rats to a total dose of 200 r at the rate of 50 r per day which resulted in an increase in enzyme activity of the spleen to 186 of normal. Cysteine, mercaptoethylamine, and 2-aminoethylisothiouronium AET were relatively ineffective in reducing the amount of change in enzyme activity in contrast to their protective effects against acute radiation injury. p-Aminopropiophenone, hydroxylamine, thyroxin, and thyroid stimulating hormones were effective antagonists of the radiation-induced injury. Progesterone and adrenal cortical extract exerted some protective action. A yeast extract and the water-soluble fractions of liver exerted marked protective effects when given parenterally but were ineffective when given orally. Author