Influence of age, sex and osteogenesis imperfecta on count, protein content, and monoamine oxidase activity of human thrombocytes.

ABSTRACT

We determined the effect of count, age (2 to 24 year), sex, and osteogenesis imperfecta (OI) on the protein content and monoamine oxidase activity in human platelets. The reaction rate in presence of paramethoxybenzylamine was assessed in a sensitive and continuously recording spectrophotometric system. Platelets harvested from control subjects and OI patients displayed significant inverse linear correlations between count and protein content; there was near-constancy of the products of the two variables. The effects of age, sex, and osteogenesis imperfecta on protein content, count, and MAO activity were assessed by multivariate analysis of variance. It was found that, with increasing age, the count increased linearly and the protein content decreased. In patients with OI the protein content was depressed and monoamine oxidase activity elevated regardless of whether the latter was calculated on the basis of pellet protein or of count. The data suggest that, in osteogenesis imperfecta, thrombocytic monoamine and protein metabolism deviate from that of controls.