The British Journal of Psychiatry 130: 151-158 (1977)
© 1977 The Royal College of Psychiatrists
Monoamine oxidase in chronic schizophrenia: Studies of hormonal and other factors affecting enzyme activity
DL Murphy, R Belmaker, WT Carpenter and RJ Wyatt
Reported reductions in the activity of platelet monoamine oxidase (MAO) in
chronic schizophrenic patients might be contributed to by alterations in
hormones, platelet numbers or other non-specific factors thought to affect
enzyme activity. In this study, MAO activity in 27 patients with chronic
schizophrenia was measured, using benzylamine as the substrate in an assay
based on platelet counts instead of platelet protein, and was found to be
markedly lower than mean MAO activity in 375 normal controls. These results
were similar to those previously reported with tryptamine as a substrate
for the enzyme. Serum testosterone, triiodothyronine, iron and iron-binding
capacity were within normal ranges in individuals with reduced MAO
activities. Platelet MAO activity remained stable over time in patients and
controls.