Fluoride-induced superoxide production in rabbit polymorphonuclear leukocytes

Fluoride-induced Superoxide (O^?₂) production in rabbit peritoneal polymorphonuclear leukocytes (PMN's) occurs in the absence of extracellular Ca²⁺. Addition of Ca²⁺ to the medium results in an inhibition of O^?₂ production. The pH during the interaction of F^? with PMN's has a strong influence on the O^?₂ production. This is not due to the dependence of the O^?₂ -producing oxidase on pH. A lowering of pH causes an increase of initial O^?₂ production and a lowering of the F^? concentration which is required to induce the O^?₂ production. Prolonged interaction with F^?, or relatively high F^? concentrations, caused an inhibition of O^?₂ production. This inhibitory effect of F^? is also favoured by a low pH. The results are compatible with the view that F^? exerts its activating and inhibitory effect after it has penetrated into the rabbit PMN's.