Effect of mating on sperm distribution in the reproductive tract of the male rat.
Extragonadal sperm reserves in male rats were measured in different regions of the genital tract before and subsequent to normal ejaculation. In sexually rested rats, the sperm count (million spermatozoa for the paired organs) in different regions was: distal vas, 18; proximal vas, 9.8; cauda epididymidis, 229; caput + corpus epididymidis, 154. Following mating, the sperm count was reduced in the proximal and distal vas deferens and in the cauda epididymidis. The reproductive tract of mated females was found to contain 29% (no copulatory plug) or 59% (with copulatory plug) of the estimated mean ejaculate, which was estimated from the difference between the sperm counts in the sexually rested rat and following ejaculation. It is concluded that in the rat the immediate source of spermatozoa for ejaculation is the cauda epididymidis, with a smaller contribution arising from the vas deferens.
D000818:Animals; D003307:Copulation; D004542:Ejaculation; D004822:Epididymis / Q000502:physiology*; D005260:Female; D008297:Male; D051381:Rats; D012726:Sexual Behavior, Animal; D013076:Sperm Count; D014649:Vas Deferens / Q000502:physiology*