Monoamine oxidase activity in the rat pineal gland: Comparison with brain areas and alteration during aging

Abstract

With benzylamine as a substrate, the amine oxidase activity was determined in the pineal gland of adult rats and compared with the same activity in brain areas and the pituitary. Two groups of rats aged 6–8 and 14–15 months were also compared on the basis of this activity. The benzylamine deaminating activity in the pineal gland was significantly higher than in the area preoptica medialis, the corpus mamillare, the tuberculum olfactorium, and the hypophysis, and was lower than in the eminentia mediana. A significant increase of the activity in the pineal gland in animals aged 6–8 to 14—15 months was revealed. Benzylamine deaminating activity in the pineal gland was totally inhibited by 0.002 mM R-deprenyl, indicating B-type monoamine oxidase (MAO B) activity. An age-associated increase of MAO B activity in the pineal gland, accompanied by decrease of glutathione peroxidase activity, which was reported earlier, can cause oxidative damage in the pineal gland during aging.