Protein kinase C blockers and neutrophil receptors for leukotriene B4

Three protein kinase C blockers (staurosporin, Cl, and sphinganine) acted temperature- and time-dependently on human neutrophils to lower the affinity and number of high affinity plasmalemma receptors available to leukotriene B4. The drugs did not alter the ligand's binding to isolated plasma membranes or reduce intact cell binding of platelet-activating factor. Thus, protein kinase C may regulate the expression of certain receptors in resting cells and blockers of this enzyme, by interfering with receptor expression, have secondary effects that complicate their use as pharmacological probes.