Physiological and Pathological Influences on Serum Monoamine Oxidase Level: Effect of Age, Sex, Contraceptive Steroids and Diabetes Mellitus

The normal serum monoamine (benzylamine and tyramine) oxidase (MAO) activity in 550 adults and 210 children was found to vary considerably with age and sex. In women using contraceptive steroids the serum MAO was significantly decreased. In 368 adults and children with diabetes mellitus the serum benzylamine oxidase level was increased. In 176 first degree relatives of persons with diabetes mellitus and in 73 persons with border line glucose tolerance tests the mean serum MAO activity was normal.