Motility induction in hamster spermatozoa from caput epididymidis : effects of forward motility protein (FMP) and calmodulin inhibitor

The motility characteristics and the behaviour of caput spermatozoa were investigated.After dilution in B 2 medium the majority of spermatozoa presented head-to- head agglutination and a twisted flagellum.Only a small population of these spermatozoa developed an anarchic motility pattern.The addition of crude bovine epididymal fluid forward motility protein (FMP) to the incubation medium suppressed flagellar angulation and agglutination.The addition of FMP to caffeine-activated spermatozoa induced a slow- swimming progressive movement in about 10 % of the spermatozoa.In order to establish an hypothetical role of FMP in the regulation of calcium transport a calmodulin inhibitor, fluphenazin, was tested.When added to caffeine-activated spermatozoa at a rate of 10-5 M, it induced about 15 % of progressive spermatozoa with flagellar angulations.The trajectories of these spermatozoa were similar to those observed in samples of spermatozoa from the cauda epididymidis.It is concluded that during epididymal maturation a calcium- dependent mechanism might be involved in the transformation of an irregular movement into a progressive movement. Introduction.Mammalian spermatozoa acquire forward motility during epididymal maturation.The spermatozoa extruded from the caput epididymidis are rarely motile (Morton, 1978) and the motility pattern observed is very often anarchic.In the hamster, we have previously provided evidence that forward motility is induced in immature spermatozoa by the dual presence of a cyclic nucleotide phosphodiesterase inhibitor, such as ' caffeine, to elevate cAMP levels, and cauda epididymal plasma in the incubation medium (Kann and Serres, 1980).Hoskins et a/.(1978) have shown that a protein present in epididymal plasma induces forward motion in washed bovine caput spermatozoa in the presence of (!) For correspondance and reprints.