Effect of melatonin on metabolic enzyme activities in different brain regions of male albino rats

Rhythmic secretion of neurohormones from brain leads to a series of perturbations in brain metabolism. Melatonin receptors show region specific diurnal rhythm in brain (Stankov et al., 1992). Physiological response of these receptors to exogenous melatonin and its action-on electrical and biosynthetic functions in brain has been documented (Cardinali, et al, 1993). Stimulatory action of exogenous melatonin on pyridoxal kinase initiates synthesis of GABA and serotonin (Quay, 1,965). However, no study have been conducted in rats and other species showing melatonin induced changes in metabolic enzyme activities in brain areas. Considering these facts, the effect of exogenous melatonin on metabolically important enzymes has been evaluated in brain areas of male albino rats.