Characterization of regional proteins in tissues and fluids in the human epididymis.

The proteins of epididymal tissues and fluids recovered from five regions of the human epididymis were separated by polyacrylamide gel electrophoresis under denaturing conditions. Among the 60 peptides identified, eight appeared to be expressed solely in the epididymal duct when compared to serum and testis proteins. Three of these (92, 47 and 24 Kd) showed a degree of regional specificity in fluids. The 92 Kd peptide was found in the caput and proximal corpus, the 47 Kd in the distal corpus and cauda and the 24 Kd in the caput of the epididymis. Three of the specific epididymal proteins (39, 30, 26 Kd) displayed a remarkable analogy to those found in man and monkey in other conditions and which are present at the sperm surface in the epididymis cauda.