Comparison of Colprimetric and Fluorometric Methods for Estimation of Sperm Concentration in Human Ejaculate and Rat Epididymal Sperm

Estimation of sperm concentration with ethidium bromide was found to be simple and rapid. The estimated value of DNA per human spermatozoon, 2.7 pg, agreed with published values. The method is also applicable to rat epididymal spermatozoa, although the apparent concentration of DNA is only 1.5 pg/spermatozoon. In spectrophotometry, falsely high values were noted. These were, however, reproducible and did not interfere with sperm estimation. Although fluorometry is not more sensitive than spectrephotometry, it is simpler, avoiding corrosive reagents, and more rapid. A standardized method is outlined and calibration equations, based on correlation analysis, are presented.