Improved analytical sensitivity reveals the occurrence of gender-related variability in diamine oxidase enzyme activity in healthy individuals

Objectives: Serum diamine oxidase (DAO; EC 1.4.3.6) activity is often employed as a clinical indicator of the integrity of intestinal mucosa. However, interindividual variation in enzyme activity and reference values for healthy women and men have not been studied. Design and methods: DAO activity was measured by using cadaverine coupled to O-dianisidine oxidation in 50 healthy individuals. Results: The mean activity was 7.59 ± 3.67 U/L for women and 2.38 ± 0.71 U/L for men (p < 0.001). Conclusions: Gender is a major determinant for DAO activity in healthy subjects.