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 B2 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.