Characterization of lithium-induced enzyme release from human polymorphonuclear leukocytes.
Lysozyme release from purified human polymorphonuclear leukocytes was found to be uniquely enhanced by 2.5-20 mM LiCl. This effect was dose dependent and was not detected when the media was supplemented with NaCl, KCl, MgCl2, or CaCl2. The purified isotopes of Li+, 6Li, and 7Li were equally effective in enhancing lysozyme release from the cells at 10 and 20 mM, but 6Li was more effective than 7Li at 5 mM. The enhancement of enzyme release in the presence of Li+ was comparable to the enhancement observed in the presence of N-formylmethionylleucylphenylalanine (fMLP). Addition of LiCl plus fMLP did not result in lysozyme release in excess of each stimulant alone, except when the cells were incubated with 20 mM 6Li + 10(-5) M fMLP. In addition, enzyme release induced by these two agents could be further enhanced to the same degree by addition of cytochalasin D to the incubation mixtures. While similarities between enzyme release induced by LiCl and fMLP were detected, optimal stimulation of enzyme release by Li+ was much more sensitive to inhibition by pertussis toxin than was maximal fMLP stimulation. Therefore, the intracellular events altered by Li+ and the peptide may share some metabolic steps, but they differ in their sensitivity to alterations in cAMP metabolism.
D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D008094:Lithium / Q000494:pharmacology*; D009113:Muramidase / Q000378:metabolism*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000201:enzymology*; D037342:Pertussis Toxin; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D010566:Virulence Factors, Bordetella; D009240:N-Formylmethionine Leucyl-Phenylalanine; D008094:Lithium; D037342:Pertussis Toxin; D009113:Muramidase