Absence of plasma amine oxidase in some frequently used animal models

1. Plasma amine oxidase (PAO), an enzyme that oxidizes primary amines is generally assumed to be present in the sera of all mammals. 2. We studied plasma from eleven different mammals to determine if they could oxidize a group of amines of biomedical interests. 3. Our results indicate that PAO is not present in all mammals and also that substrate specificity of the enzyme varies within the species tested. Rodents which are frequently used as animal models in pharmacology and toxicology do not contain PAO. 4. The common polyamines, spermine, spermidine and putrecine were oxidized only by bovine plasma.