Gossypol-induced inhibition of plasminogen activator activity in human and ovine acrosomal extract

Abstract

The effect of gossypol-a polycyclic compound isolated from cotton seeds-on the plasminogen activator activity of man and ram acrosomal extracts was explored in vitro. The action of gossypol on the plasminogen activator activity was investigated by a spectrophotometric method using the chromogenic substrate S-2251. Gossypol, a known antispermatogenic agent, was found to effectively inhibit human and ovine acrosomal plasminogen activator activity. The inhibition was dose-dependent. Plasminogen activator activity from man and ram extracts was completely inhibited by 350 mu mol l(-1) and 300 mu mol l(-1) of gossypol, respectively. In additional experiments, low, non-spermicidal concentrations of gossypol (2.5-40 mu mol l(-1)) were found to significantly inhibit plasmin activity in a dose-dependent manner. The results suggest that inhibition of both acrosomal plasminogen activator and plasmin activity is a possible mechanism by which gossypol exerts its antifertility effect, since the plasminogen activator/plasmin system plays a role in the whole process of ovum fertilization.