Influence of X-Radiation on Development of Enzymes Responsible for Desulfuration of an Organic Phosphorothioate and Reduction of p-Nitrobenzoic Acid in the Livers of Male Rats

Abstract

The effect of x-ray on the development of enzymes re-sponsible for desulfuration of Guthion, a phosphorothioate, to its oxygen analog and for reduction of p-nitrobenzoic acid to p-aminobenzoic acid was investigated. 200 r or 400 r of X-radiation in 23-day old male rats almost completely inhibited the 3-fold increase in phosphorothio-ate-desulfuration activity normally observed by 45 days of age. The livers of animals given 100 r also exhibited substantial inhibition of developing enzyme activity. Unradiated rats reached adult enzyme levels at 45 days of age. Animals given 100 r or 200 r did not develop nor-mal adult activity until they were 53 to 58 days old. Administration of 200 r, 400 r and 600 r of X-ray, at 2 days after hepatectomy, inhibited the regeneration of enzyme activity by 22%, 51% and 78% respectively, at 10 days after hepatectomy. X-ray had no inhibitory effect on the phosphorothioate-desulfuration enzyme activity of adult male rats. These results suggest that the effect of X-ray is on the development of the enzyme-synthesizing process. 400 r at 14 or 23 days of age had no effect on the development of reductase activity.