Differences in the rate of redistribution of receptors for concanavalin A in vivo and in vitro on spermatozoa from normal mice and from sterile mice carrying different T/t locus haplotypes

The redistribution of receptors for fluorescein isothiocyanate‐conjugated concanavalin A (FITC‐con A) on mouse spermatozoa during maturation has been studied in vivo and in vitro using normal mice and sterile mice carrying two different lethal T‐locus haplotypes (tx/ty). Receptors for FITC‐con A, uniformly distributed on the head of functionally immature sperm within the proximal epididymis, become localized as the cells acquire functional maturity within the distal portion of the epididymis. Examining samples of epididymal sperm incubated for short periods of time in vitro, a similar increase in the proportion of discretely labeled cells is observed with time. Sperm from sterile tx/ty males also show redistribution of receptors for FITC‐con A in vivo and in vitro; however, a significantly smaller proportion of cells of the population achieve a discrete distribution of receptors comparable to that displayed on sperm from fertile mice. It is concluded that mouse sperm undergo redistribution of receptors for con A normally in acquiring functional maturity within the epididymis and upon liberation from the male urogenital tract; the sterility of tx/ty mice may be due to a genetically based impairment of plasma membrane reorganization reflected in sluggish redistribution of receptors for con A shown by these cells in vivo and in vitro.