| Abstract: | Superoxide anion production in peritoneal polymorphonuclear leukocytes obtained from guinea pigs was stimulated by in vitro treatment with membrane-perturbing agents, such as cytochalasin D, concanavalin A, phorbol myristate acetate, myristate, digitonin, and NaF. Vinblastine modified these stimulating effects on the superoxide anion production, but its modifying effect was not uniform. The effect of cytochalasin D was stimulated by vinblastine at the concentration of 10(-5)-10(-7) M, whereas it was inhibited at the concentration of 10(-4) M. At 10(-4)-10(-5) M, vinblastine was inhibitory to the effect of concanavalin A, and lower concentrations had no significant effect. Stimulation of the superoxide anion production by phorbol myristate acetate and myristate was further enhanced by vinblastine at any concentration in the range of 10(-4)-10(-8) M with peaks at 10(-6) and 10(-5) M, respectively. Vinblastine had little effect on the stimulation of the superoxide anion production by digitonin and NaF throughout the concentration range examined. The mechanism of the interaction of these membrane-perturbing stimulants and vinblastine is discussed. |
