[Biochemical and clinical aspects of melatonin biosynthesis induced by noradrenalin in experiment]

Melatonin has been considered as a hormone with potent immunomodulating, anxiolitic and antioxidative properties. Melatonin is also known to be inhibitor of sympatoadrenal activity. The study was aimed to elucidate changes in melatonin synthesis induced by noradrenalin IM injection. Melatonin plasma levels were detected by radioimmunoassay. All studies were performed conducted on white non-linear rats. By the 20th day after noradrenalin administration plasma level of melatonin was significantly decreased. In conclusion, short-term activation of sympatoadrenal system (i.e. stress-induced activation) is accompanied by elevated plasma levels of melatonin, however long-term hyperactivity of the sympatoadrenal system atrophy of epiphiseal parenchyma develops followed by decreased melatonin synthesis. It has been considered that melatonin might contribute to chronic stress-induced process associated with involution of thymus and lymphatic nodes, hypertrophy of adrenal cortex. Data obtained might be taken into consideration during the treatment of stress-induced conditions.