[New concepts about the terminal mechanism of fertilization in mammals]

We briefly reviewed some ionic mechanisms participating in the fulfillment of the acrosome reaction processes, indicating the results obtained by the simultaneous and dynamic quantitation of sodium, potassium, calcium and hydrogen concentrations in the in incubation medium of human spermatozoa induced to achieve the acrosome reaction through the addition of cAMP and follicular fluid. At the same time, the participation of zinc and some enzymatic activities, like phospholipase A2, in the occurrence of this process, is indicated. A study is done about the sperm nuclear decondensation mechanisms, pointing at the importance of various participants in this event, like the disulfide groups reducing agents, some metal ions and the glycosaminoglycans, as well as a proposal of a mechanism which could be physiologically functional for the in vivo occurrence of this phenomenon. Finally we present some results explaining the DNA synthesis activation, which is repressed in the spermatozoa since the spermiogenesis final stages, and is indispensable for the chromosomic duplication required during egg segmentation.