Seminal plasma creatine kinase activity in fertility studies.

Creatine kinase activity was measured in the seminal fluid of 70 males undergoing fertility studies. The average value obtained at 30 degrees C was 333 +/- 197 IU/l (average +/- SD). There was no evidence of a significant correlation between creatine kinase enzymatic activity and density, active lineal motility, or number of normal motile spermatozoa; nor was there any correlation seen between creatine kinase activity and concentration of citric acid, (indicator of prostatic function) or fructose, (indicator of seminal vesicle function). Nonetheless, in two cases of excretory azoospermia, very high values of creatine kinase (2510 and 1280 IU/l) and citric acid levels (4000 and 3000 mg/dl) were observed. These would indicate that the origin of creatine kinase is fundamentally prostatic, in contradiction to previous studies by other authors. In this sense, creatine kinase would be a parameter of prostatic function in studies of male fertility. In two cases of secretory azoospermia due to cryptorchidism and in several very severe oligoasthenozoospermias, low creatine kinase levels were seen, while fructose and citric acid levels were normal. This would give relative value to creatine kinase as an indicator of spermatogenesis.