Macromolecular Secretion into Various Segments of the Guinea Pig Epididymis

The secretion of proteins of different segments of the guinea pig epididymis was studied using micropuncture and radiochemical techniques. Tissue and fluid samples were taken 24-48 hr after intraperitoneal injections of 2 mCi of tritiated lysine. Macromolecular secretion was higher in the caput than in the corpus and cauda. Labelled spermatozoa were detected in smears taken from the caput epididymis 24 hr after injection. Few labelled spermatozoa were found in the corpus and none in the cauda. Since the capacity of epididy mal sperm for fertilization is apparently achieved before spermatozoa reach the cauda, the protein synthesized in the epididymal caput and corpus would account for triggering sperm maturation.