Some aspects of the pharmacology of semicarbazide-sensitive amine oxidases.

Semicarbazide-sensitive amine oxidase enzymes (SSAO) are found in animals, plants, fungi and bacteria. In vertebrates, their distribution in tissues and blood plasma varies between species. Studies of the SSAO enzymes have concentrated on their biochemical identities separate from those of MAO. Attention is now being paid to their possible physiological and pharmacological significance. These may include, besides the scavenging of circulating amines, functions dependent upon the hydrogen peroxide these enzymes produce. Modulation, by SSAO, of blood vessel tone may be due to the control of amine concentration itself or to actions of released peroxide. In the plasma the activity of SSAO may be susceptible to hormonal control as well as being an indicator of copper status of the animal. However, SSAO may convert xenobiotics to more toxic metabolites. Use of highly selective SSAO inhibitors, such as procarbazine and B24 should enable these preliminary observations to be examined further.