ANNUAL VARIATIONS OF CEREBRAL AND RENAL ALKALINE-PHOSPHATASE AND GAMMA-GLUTAMYL-TRANSPEPTIDASE ACTIVITIES IN RATS

This work was undertaken to study annual variations of cerebral and re nal enzymatic markers in rats. Cerebral gamma-glutamyltranspeptidase a ctivity levels presented two peaks: in June and December (+167%,p<0,05 ),with minima in February and April (0%), and a mean of 89%. Cerebral alkaline phosphatase activity was highest in June (+125%, p<0,05) and lowest in February (000%) and a mean of 52%. Renal gamma-glutamyltrans peptidase activity was highest from June to August (+125%, p<0.05) and lowest in February (000%) and a mean of 79%. Whereas renal alkaline p hosphatase activity peaked in October (+28%, p<0.05) with a minimum in August (000%) and a mean of 16%. These variations could be related to an endogenous oscillator, the melatonin pulsatile secretion and to di fferent levels of 25-hydroxyvitamin D-3 during the whole year.