[Phosphatase activity in bone tissue and blood serum during 90-day hypokinesia].

Activities of alkaline and acid phosphatases in femoral epiphysis and diaphysis and those of alkaline phosphatase in the serum of rats that were exposed to a 3-month hypokinesia were measured. Phasic changes in the phosphatase activities were found in bone tissue. During the beginning of the hypokinetic experiment activities of both enzymes decreased as compared with the controls, the decrease of alkaline phosphatase being more significant. After the stress period activities of both phosphatases increased (especially of acid phosphatase in diaphysis) and by the end of the experiment were higher than the level of the enzyme activity in control rats. The activity of alkaline phosphatase in the serum varied in parallel with the enzyme activity in bones. The results give evidence for significant metabolic changes in the bone tissue during hypokinesia which lead to predominant resorption processes.