Influence of age on sperm concentration in the male golden hamster

Male golden hamsters were separated into three age groups: adolescent, 2-4 months; adult, 12-13 months; aged 20-24 months, and maintained on a reversed light cycle. Body, testis and epididymal weights were recorded at the time of sacrifice. Stock suspensions of sperm were obtained from the cauda epididymidis and serially diluted in saline. Optical density (O.D.) readings and sperm counts were taken for each dilution sample. Data points, O.D. versus sperm counts, were computer fit. Comparison of the regression lines demonstrated a significant difference between the slopes of curves for adolescent males and for adult and aged males (99% confidence level). Mean sperm counts for the adult and aged males were significantly higher than for the young males. The increased counts were accompanied by decreases in O.D. with advancing age. Trypsin treatment of the sperm revealed no effect on O.D. indicating that separation of heads and tails was not responsible for the change in O.D. values of sperm samples. Likewise, comparison of washed and unwashed sperm indicated that epididymal fluid plays no role in determining O.D. values. There were no significant age-related differences in body, testis or epididymal weights.