BONE TISSUE REMODELING AFTER THE INTRODUCTION OF EXOGENOUS MELATONIN IN DIFFERENT SEASONS.

We studied the impact of pharmacological doses (5 mg / kg) of melatonin on the parameters of bone remodeling in 3 month-old male Wistar rats in autumn and spring. In autumn experiments, introduction of melatonin to young rats caused an increase of alkaline phosphatase by 43,9% and hialuronidase activity by 15,4% and decreased the content of glycosaminoglycans by 46,7%. The concentration of total lipids and triglycerides was decreased. In spring, the introduction of melatonin to young rats inhibited the physiological remodeling of bone tissue, reduced the activity of alkaline phosphatase and increased the activity of acid on the 78% and tartrate resistant acid phosphatases by 72% regardless of the oxygen consumption level. The concentration of glycosaminoglycans and free amino acids increased. Such changes may disturb the integrity of the organic matrix and reduce the fixation of inorganic component of connective tissue – hydroxyapatite crystals.