Enhanced seminal plasma ribonuclease activities in azoospermia, severe oligiozoospermia, and asthenozoospermia.

Acid and alkaline ribonuclease (RNAase) activities were measured in human seminal plasma. The samples were obtained from patients attending an Infertility Clinic and were separated into groups according to the concentration and motility of spermatozoa. Levels of acid and alkaline RNAase activities in seminal plasma were, respectively, 22 and 13 times the values found in blood plasma. The severe oligozoospermic and azoospermic groups showed significantly higher alkaline RNAase activities in the seminal plasma than the normozoospermic group. The group with sperm motility < 50% showed significantly higher acid and alkaline RNAase activities than the group with motility greater than or equal to 50%. Enhanced RNAase activities may be involved in the process of bringing about a reduced formation and maturation and a reduced motility of spermatozoa.