with Earle’s salts supplemented with 10% (vol/vol)
bovine steer serum, 2 mg/mL estradiol 17-b, 20 mg/mL
bovine follicle stimulating hormone (Folltropin-V; Bioniche),
22 mg/mL sodium pyruvate, 50 mg/mL gentamicin
sulfate, and 1 mM glutamine. Percoll was from Amersham
Pharmacia Biotech (Uppsala, Sweden). Potassium simplex
optimized medium (KSOM) that contained 1 mg/mL BSA
was from Caisson Laboratories Inc. On the day of use, KSOM
was modified to produce KSOM-BE2 as described previously
[14]. Synthetic oviductal fluid [15] was purchased as
a custom formulation from Millipore (Billerica, MA, USA).
Lidocaine was from Pro Labs (St. Joseph, MO, USA).