Recent studies of sperm chemotaxis in mammals

Sperm ehemotaxis ean occur only after the release of an egg ready to be fertilized (ovulation). However, all published studies were carried out with foUieular fluids containing substances secreted within the follicle prior to ovulation. For this reason it was relieving when Sun et al. [ 162] demonstrated human sperm chemotaxis to conditioned media of human cumulus-oocyte cells, i.e., media pre-incubated with mature eggs, their surrounding cumulus cells, or both. These media, therefore, contain secretions of cumulus cells and mature, ready-to-be-fertilized eggs. 

Ralt aZ. [128] Human + Accumulation (ascending 6c descending), choice, directionality + 

An intriguing observation was made a few years ago by Oliveira et al. [114] with mouse spermatozoa. They found that not only mouse follicular fluid, but also mouse oviductal fluid attracts spermatozoa by chemotaxis. This finding raised the possibility that sperm chemotaxis within the female genital tract occurs in steps [114]. This possibility of sequential chemotaxis awaits further evidence. 

Substance Species Assay type Reference Chemotaxis criterion fiilflUed 

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