[Epididymal maturation of human spermatozoa]

The role of the human epididymis in spermatozoa maturation is demonstrated by means of several sperm function tests, with the aid of which, the various stages in the fertilization process can be mimicked. Accordingly, as they pass through the epididymis, spermatozoa become progressively more motile--which can be enhanced by the addition of phosphatidylcholine--inducibility of the acrosome reaction increases, and chromatin condensation is completed. Capability of fusing with the ovum is observed for spermatozoa from the epididymis, but not for those from the caput epididymis, while the spermatozoa from the latter already have normal acrosine activity. Ability to bind to the zona pellucida has not been adequately clarified. These results demonstrate the significance of the human epididymis for sperm maturation, even though a small percentage seem to reach adequate maturity in the caput epididymis.