Abstract
A method for estimating the concentration of spermatozoa in the rat cauda epididymidis is described. Treatment of a sperm suspension with 0·05% collagenase for 20-60 min or 0·025% trypsin for 1-2 min at 34-37°C was found to result in consistently homogeneous sperm. Sperm concentration ranged from 152·5 to 230·0 × 107 spermatozoa/ml, with a mean of 187·7 (±5·6 SEM)×107 spermatozoa/mI.