Response of the mouse epididymal duct to the disappearance and reappearance of spermatozoa induced by temporal cryptorchidism.
Cryptorchid surgery to move the testis and epididymis to the abdomen was performed in mice of 60 days of age; one week later the mice were subjected to further surgery to reposition the organs in the scrotum. The mice were sacrificed at 1 week intervals until 11 weeks after the initial operation. After the first operation, spermatozoa in the epididymal duct rapidly disappeared and were almost absent until the 4th week. Then spermatozoa appeared again, increased, and reached normal numbers by 10 weeks. With the disappearance of the spermatozoa, a PAS-positive material, which is believed to be secreted in the middle part of the head of the epididymal duct (ABE et al., 1982), was accumulated in the epididymal duct in the body and tail of the epididymis, and PAS-positive inclusions appeared in the principal cells of the duct in the body 2 weeks after the first operation. The inclusions developed in size and number during the aspermia period, then decreased in number with the reappearance of spermatozoa from the 5th week to ultimately disappear by 10 weeks after the first operation. We have previously demonstrated that such inclusions appear also after efferent duct ligation, which interrupts the flow of spermatozoa and testicular fluid into the epididymal duct (ABE et al., 1982). Both present and previous findings indicate that the appearance of PAS-positive inclusions depends on the absence of spermatozoa in the epididymal duct irrespective of the presence of the testicular fluid in the duct. It is suggested that the PAS-positive material is utilized by spermatozoa and, in the absence of spermatozoa, is accumulated in the lumen and ingested by the principal cells of the epididymal duct in the body of the epididymis.