ABSTRACT
This chapter describes the involvement of diamine oxidase (DAO) and the presumed role of its main substrates, putrescine and histamine, in growing tissue in model situations, such as tissue culture, fetal growth, and normal tissue growth and development in an adult organism. DAO is responsible for oxidative deamination of putrescine and histamine to aldehydes. An enhancement of DAO activity should decrease histamine levels with a concomitant imidazoleacetic acid and/or histaminol increase, while the inhibition of DAO activity should increase tissue histamine level. High DAO activity found in fetal tissues at the end of pregnancy raises questions con cerning the role of the enzyme in developmental physiology. The polyamine-oxidized products, derived from semen diamine oxidase reaction, have been found to influence the behavior and metabolism of spermatozoa. Diamine oxidase activity appears also in fetal tissues. In the guinea pig fetus, DAO can usually be detected in measurable quantities in liver in the middle of gestation.
