Serum alkaline phosphatase as a diagnostic criterion in experimental radiation disease

In the serum of full grown male Wistar rats irradiated with 60Co (100, 30a, 500 and 800 R) and in a control group the activity of serum alkaline phosphatase and its isoenzymes was investigated at various time intervals after irradiation. Changes in the general activity had a phasic character. A statistically significant drop of activity was found between the 2nd and 5th day after 500 R and permanently from the 2nd day after irradiation with 800 R. Changes in the activity of the intestinal and liver isoenzyme also had a phasic character. The activity of the intestinal isoenzyme declined significantly already on the first day after irradiation with 300 R and higher doses; the drop on the 2nd day after irradiation with 100 R was significant at the 5% level of significance. Investigation of the activity of the intestinal isoenzyme can be used as a rough biological dosimeter. The serum activity of the hepatic isoenzyme declined significantly on the 3rd to 5th day after irradiation with 500 and 800 R, which is in keeping with changes of the enzyme activity in the liver. After a dose of 800 R a progressing decline of activity of the bone isoenzyme was found even after 100 and 500 R. The findings are typical for the development of the gastrointestinal and osseous radiation syndrome. They may be used for the evaluation of the effect of radioprotective substances and therapeutic procedures and as a simple biochemical diagnostic and prognostic criterion of the action of ionizing radiation in experiments on rats. (author)