Progesterone accelerates the onset of capacitation in mouse sperm via T-type calcium channels

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.