Effect of protein kinase C stimulators on zona pellucida binding and the acrosome reaction of macaque sperm.

Macaque sperm require treatment with dibutyryl cAMP (dbcAMP) and caffeine (termed activators; ACT) to fully capacitate in vitro. Previous studies have shown that treatment with ACT also increases sperm binding to the macaque zona pellucida and enhances the induction of acrosome reactions of the bound sperm. This study investigated whether phorbol 12-myristate 13-acetate (PMA) and 1,2-dioctanoyl-sn-glycerol (DOG), which stimulate protein kinase C (PKC), can also increase sperm binding to the zona pellucida and/or enhance induction of the acrosome reaction of bound sperm. Cynomolgus macaque sperm were centrifuged through 60% Percoll and then were washed with modified Biggers, Whitten and Whittingham (BWW) medium and incubated for 2.5 h at 37 degrees C with 5% CO2, ACT, PMA, or DOG was added to sperm during the last 15-30 min of incubation. Sperm were evaluated immediately after incubation for motility and acrosomal status. Macaque oocytes were coincubated with stimulated sperm suspensions in BWW medium for 30 sec (pulse). Half of the oocytes were removed to sperm-free medium and further incubated for 1 h (chase). When assessed after the pulse period, sperm-zona binding increased significantly after ACT treatment compared to that in untreated controls. DOG but not PMA treatment had a similar effect on sperm binding PMA, DOG, and ACT treatment increased the percentage of acrosome reactions in sperm bound to the zona following the 30-sec pulse compared to the percentage in controls. Inactive analogs of PMA and DOG had no effect on sperm-zona binding or the percentage of acrosome reactions (% AR) of bound sperm.(ABSTRACT TRUNCATED AT 250 WORDS)