Fig. 3. GalT I-null sperm are more sensitive to Ca²⁺ ionophore than wild-type sperm during in vitro capacitation. Wild-type (gt +/+) and GalT I-null (gt –/–) sperm were capacitated for varying periods of time before incubation with 10 µM A23187 or an equal volume of DMSO. GalT I-null sperm show higher basal levels of sensitivity to ionophore-induced acrosome reactions, as well as greater sensitivity during capacitation in vitro. Each point represents the mean±s.e.m.; n=3 experiments. In a single experiment, the value of each data point represents three determinations. Thus, each data point reflects data collected from nine assays, each containing 200 sperm counted. *P<0.01.