Levels of carnitine acetyltransferase in fertile and oligospermic infertile semen.

Activities of carnitine acetyltransferase (CAT) were determined in fertile (greater than 40 X 10(6) sperm/ml) and oligospermic infertile semen (less than 15 X 10(6) sperm/ml). CAT specific activities (unit/10(6) sperm) appear to be similar in both kinds of semen i.e., 0.020 +/- 0.002 and 0.013 +/- 0.001 for fertile and oligospermic infertile sperm, respectively. When CAT activities were corrected as unit/mg protein and unit/mg DNA, the values in the fertile sperm were 0.130 +/- 0.010 and 8.97 +/- 0.50, respectively, while in the infertile sperm the values were 0.016 +/- 0.002 and 2.72 +/- 0.14. The lower value in the oligospermic infertile sperm is due to the much higher amount of these macromolecules in infertile sperm. On the other hand, CAT activities and the amount of protein appear to be similar in both fertile and oligospermic seminal plasma. Our results, therefore, suggest that the lower level of CAT in infertile semen is due to its lower sperm density.