[Studies on diamine oxidase (DAO) activity in seminal plasma].

Diamine oxidase (DAO: EC 1.4.3.6) activity was measured for seminal plasma of patients complaining of infertility to investigate whether measurement of DAO activity in seminal plasma is a significant laboratory examination or not for evaluation of male infertility. (1) DAO activity showed a slight decrease with increasing sperm density, but there was no significant correlation between DAO activity and sperm density. (2) DAO activity was higher in samples with sperm motility below 20%. There was a significant negative correlation between DAO activity and sperm motility. (3) DAO activity was higher in samples with motile sperm count below 10 x 10/ml. In conclusion, the simple spectrophotometric assays for DAO could form the base of a routine examination of male infertility.