Increased activity of monoamine oxidase by epoxy resin hardeners.

In order to investigate the potency of amines to cause metabolic changes which are related to scleroderma, serum monoamine oxidase (MAO) activity to workers in an epoxy resin handling process was measured. Mean serum MAO activity of 15 workers exposed to amine was 33.5 +/- 6.4 units, whilst that of control workers was 28.9 +/- 7.8 (P less than 0.05). The finding was confirmed in an in vitro experiment. After 24 h treatment with amine, the MAO activity of cultured skin fibroblasts was elevated in a dose-response manner. These results suggested the potency of amine to produce an increase in MAO activity, and this phenomenon seems to be related to the cases of occupational scleroderma-like disorder which were observed in an epoxy resin polymerizing process.