Effects of gossypol on phorbol ester-calcimycin-induced prostaglandin synthesis by macrophages.

Arachidonic acid metabolism via cyclooxygenase pathway in mouse resident peritoneal macrophages were stimulated by phorbol-12-myristate-13-acetate (PMA), calcimycin and exogenous arachidonic acid, respectively. Racemic, (-) and (+)-gossypol dose-dependently inhibited PMA or calcimycin-induced synthesis of prostacyclin, thromboxane A2 and prostaglandin F2 alpha, but failed to affect arachidonic acid-induced synthesis of prostaglandin. It is suggested that both (-)-gossypol and (+)-gossypol inhibit synthesis of prostaglandin at the level of arachidonic acid release, and the inhibition of prostaglandin synthesis by gossypol might not be the main mode of its antifertility action.