A radioenzymatic assay of catechol-O-methyltransferase in hair root cells: comparison with erythrocyte activity.

A sensitive radioenzymatic assay of catechol-O-methyltransferase (COMT) in hair root cells is presented. Only five hair roots with intact bulb and sheath are needed for one assay. By pulling 15-20 hairs, 3-4 parallel assays can be performed. As in erythrocytes the COMT activity in hair root cells is constant for each individual. Nevertheless, there is no high correlation between the enzyme activities in erythrocyte and in hair root cells (r = 0.26, 0.1 greater than P greater than 0.05, N = 46). The determination of COMT in hair root cells offers a further application of this source in genetic research, as in the study of a correlation between COMT activity and various endogenous psychiatric disorders.