Creatine kinase isoforms in the seminal plasma and the purified human sperm

In previous conventional reports sperm and seminal plasma were not well separated and therefore it was highly probable that isoform (CK-BB) of seminal plasma was determined together with that of sperm. The authors developed a method to purify sperm specimen free from seminal plasma. Human sperm was purified by means of the continuous-step density gradient centrifugation with an inner column and the subsequent modified swim-up procedure. CK isoforms in the purified sperm and the seminal plasma were analyzed by ion exchange chromatography and electrophoresis. The purified sperm contained mitochondrial CK-MiMi as well as cytosolic CK, of which isoform was almost occupied by CK-MM but CK-BB was not detected. On the other hand, CK isoform in the seminal plasma was detected as CK-BB alone. CK activity in human sperm and seminal plasma were 2.0 +/- 0.7 x 10(-6) IU/10(6) sperm and 661 +/- 360 IU/L, respectively. CK activity in the seminal plasma gave no correlation with the semen parameters.