Passage and disappearance of labelled spermatozoa in the genital tract of the male Japanese quail in segregation or cohabitation.

Male quails kept in segregation from or in cohabitation with females were injected with 3H-thymidine and the passage of labelled spermatozoa through the epididymis and the vas deferens was followed by autoradiography. Labelled spermatozoa appeared in the epididymis on the 11th day after injection and reached the distal part of the vas deferens within 2¢ hours both in segregated males and in those kept with females. Three sperm populations with decreasing intensity of labelling were identified in the epididymis on days I 1 , 14 and IS, and in the distal part of the vas deferens on days xz, i5 and x6 after injection. From the distribution of labelled spermatozoa along the vas deferens of the males of the two groups, it was concluded that some slowing down in the transit of the main bulk of the spermatozoa had occurred in the males kept isolated from females. This fact indicated the role of the vas deferens as a transitory storage place of the segregated males, unejaculated spermatozoa which were eliminated about 24 h later than those of the males kept in cohabitation with females.