Maturation-dependent goat epididymal sperm autoagglutination and its inhibition by a glycoprotein factor.

The maturing goat epididymal spermatozoa were isolated from different segments of epididymis and these cells dispersed in a modified Ringer's solution, were incubated at 37 degrees C for 60 min to evaluate their autoagglutination efficacy. Distal corpus-epididymal spermatozoa specifically showed high order of head-to-head autoagglutination property whereas all other sperm cells did not show any detectable aggregation. The goat epididymal plasma has been shown to possess an anti-agglutinin that markedly inhibits sperm agglutination phenomenon and also dissociates the cells from the sperm clusters. Epididymal plasma is the most potent source of the anti-agglutinin which is a heat-stable specific glycoprotein. Like the autoagglutination phenomenon, the initiation of sperm forward progression also starts in the distal-corpus epididymis. The temporal correlation of these two events suggests that sperm autoagglutination may be a prerequisite for the induction of flagellar motility during the epididymal maturity of male gametes.

Dephosphorylation of cell-surface phosphoproteins of goat spermatozoa.

Multiple ecto-phosphoproteins of the goat cauda-epididymal intact spermatozoa have been shown to undergo dephosphorylation in vitro by endogenous phosphoprotein phosphatase(s) located on the sperm outer surface. The major ecto-phosphoproteins that are dephosphorylated have molecular masses of 27, 40, 70, 116 and 205 kDa. The cell surface dephosphorylation reaction is not dependent on bivalent metal ions. Mg2+ (5 mM), Mn2+ (5 mM), orthovanadate (200 μΜ) and cAMP (5 μΜ) have no effect on this surface reaction whereas it is inhibited nearly 50% by Co2+ or Zn2+ (1 mM). Spermidine (5 mM), or Ca2+ (1mM) inhibited to a small extent (approx. 25%) the cell surface dephosphorylation of proteins.