Alterations in protein profile of rat spermatozoa during maturation

Alterations in the polypeptide pattern of rat spermatozoa during epididymal transit were studied by SDS-PAGE and compared with that of epididymal cytosol and luminal fluid. The total number of cytosol and luminal fluid polypeptides increase from caput to cauda epididymidis but sperm associated polypeptides decrease during epididymal transit. Changes in polypeptide pattern of spermatozoa are due to their acquisition, loss or modification. Spermatozoa acquire seven polypeptides, of which six are acquired in corpus (MW 16.5, 38, 41, 72, 75 and 100 Kdal) and one (MW 28.5 Kdal) in cauda epididymidis. Spermatozoa lose one polypeptide of MW 72.5 Kdal in caput and two polypeptides of MW 70 and 115 Kdal in cauda epididymidis. Four polypeptides of MW 18.5, 19.5, 64 and 67.5 Kdal disappear from cauda spermatozoa without appearing in the luminal fluid. Polypeptide of MW 62.5 Kdal is observed only in spermatozoa and luminal fluid from cauda epididymidis.