Changes in specific amino acid residues and Na+, K(+)-ATPase activity in cell membranes of rat cerebral cortex by low dose X-irradiation.

This study examines the influence of low dose X-irradiation on the structure and transport function of cell membranes of rat cerebral cortex. We found that unlike high dose irradiation which promotes membrane damage, low dose irradiation stimulates the SH group of membrane proteins and enhances the ability to control the membrane transport mechanism as reflected by an increase in Na+, K(+)-ATPase activity. The concentration of cysteine (Cys) significantly increased at 25-100 cGy and the concentration of cystine (Cys-Cys) significantly decreased at 25 cGy. It showed no dose dependent changes in tyrosine (Tyr), phenylalanine (Phe) and glycine (Gly). Similarly phospholipid and cholesterol levels were unchanged. Na+, K(+)-ATPase activities significantly decreased at 100 cGy or higher but significantly increased at doses of 25 and 50 cGy.