EXPRESSION OF SCATTER FACTOR HEPATOCYTE GROWTH-FACTOR IS REGIONALLY CORRELATED WITH THE INITIATION OF SPERM MOTILITY IN MURINE MALE GENITAL-TRACT - IS SCATTER FACTOR HEPATOCYTE GROWTH-FACTOR INVOLVED IN INITIATION OF SPERM MOTILITY

Based upon findings that the scatter factor/hepatocyte growth factor ( SF/HGF) has strong mitogenic and motogenic properties, and that the sp erm cell acquires its fertilizing capacity and motility in the distal parts of mammalian epididymis, the present study was conducted to inve stigate the role of SF/HGF in initiation of sperm cell motility. This was investigated by determining the expression of SF/HGF in various re gions of the murine male genital tract by scatter and cell tracking as says using MDCK epithelial cells, Western blot procedure, and the immu nohistochemical procedure using paraffin sections of various regions o f the male genital tract. The findings from all these assays indicate that SF/HGF is differentially expressed in various parts of the male g enital tract with slight or no expression in the testes, caput epididy mis, and vas deferens, and with the highest expression in cauda and co rpus (distal) epididymis followed by expression in the corpus (proxima l) epididymis. This region-specific SF/HGF expression pattern coincide s with the pattern of acquiring the fertilizing capacity and motility by the sperm cell during its transit through the male genital tract. H owever, wherever SF/HGF was expressed in the male genital tract, its m olecular weight was slightly higher (Mr, 82 kD), compared to the SF/HG F expressed in various other somatic tissues (Mr, 78 kD), indicating t hat the genital tract SF/HGF may be a different molecular species that shares some immunoreactive epitopes with the somatic cell SF/HGF. Inc ubation of immotile sperm from caput epididymis with the purified huma n placental SF/HGF of 78 kD initiated motility in 5-15% of sperm popul ation. These results strongly suggest that the SF/HGF-like activity is expressed in the male genital tract in a region-specific manner, and this activity may have a role in initiation of sperm motility acquired during its transit through the epididymis in mammals. (C) 1994 Wiley- Liss, Inc.