DIRECT EVIDENCE FOR THE SECRETION OF LACTOFERRIN AND ITS BINDING TO SPERM IN THE PORCINE EPIDIDYMIS

Lactoferrin has been for the first time purified from the porcine caud a epididymal fluid as a 70 kDa protein. Both Western and Northern blot analyses show that lactoferrin is synthesized in the regions from the distal caput to the cauda epididymis and secreted into the luminal fl uid. Lactoferrin is first secreted as a 75 kDa glycoprotein and its ca rbohydrate moieties are gradually digested to form 70 kDa protein in t he cauda epididymis. Lactoferrin has already bound to the surface of t he epididymal sperm because the anti-lactoferrin antiserum induces the mature sperm tail-to-tail agglutination. These results strongly sugge st new physiological functions of lactoferrin on the sperm maturation in the epididymis. (C) 1997 Wiley-Liss, Inc.