AJP - Regulatory, Integrative and Comparative Physiology, Vol 242, Issue 3 199-R203, Copyright © 1982 by American Physiological Society
Sperm motility-inhibiting factor in rat epididymis
T. T. Turner and R. D. Giles
Rat spermatozoa collected by micropuncture from the cauda epididymidis are
immotile when diluted in cell-free cauda epididymidal fluid but are
vigorously motile when diluted in 0.154 M NaCl. Removal of proteins from
cauda fluid by heat precipitation or enzymatic digestion reduces the
ability of cauda fluid to keep cauda sperm immotile. Cauda sperm diluted in
trypsin-treated cauda fluid have motility initiation scores that are not
significantly different (P less than 0.05) from cauda sperm motility scores
after dilution in 0.154 M NaCl. Cell-free lumen fluids from the proximal
epididymis have a reduced ability to enforce quiesence on cauda
spermatozoa, and rete testis fluid does not keep cauda sperm immotile.
However, concentrated rete testis fluid does prevent the initiation of
motility. It is proposed that a proteinaceous factor, possibly of
testicular origin, is important in preventing the initiation of motility
while sperm reside in the distal reproductive tract of the male rat.
