[Gamma-aminobutyric acid level and glutamate decarboxylase activity in the plasma of healthy persons].

Content of gamma-aminobutyric acid in blood plasma of healthy persons did not depend on sex and age and of women--on the phase of menstrual cycle. Activity of glutamate decarboxylase was higher 1.5-fold in blood plasma of women as compared with that of men values; a decrease in the enzymatic activity was observed in men after 30 years old and in women--after 40 years old. Activity of glutamate decarboxylase was higher in blood plasma of young and middle age women during the lutein phase of menstrual cycle as compared with the follicular phase, while this ratio reversed its direction in blood plasma of older women as a result of distinct decrease in the enzymatic activity during the lutein phase of the cycle.