Diacylglycerol mass measurements in stimulated HL-60 phagocytes.
The mass of sn-1,2-diacylglycerol in crude lipid extracts from differentiated HL-60 phagocytes was measured by quantitative conversion of the diacylglycerol to [32P]-labeled phosphatidic acid catalyzed by E. coli diacylglycerol kinase. The chemotactic peptide N-formyl-Met-Leu-Phe caused a time- and concentration-dependent increase in diacylglycerol that was maximal at 4 min. Diacylglycerol returned toward basal levels by 15 min. The basal level of diacylglycerol was 290 +/- 25 pmol/10(7) cells (n = 36). Maximally effective concentrations of N-formyl-Met-Leu-Phe and N-formyl-Nle-Leu-Phe-Nle-Tyr-Lys increased diacylglycerol to 176% +/- 16 of basal (n = 8) and 198% +/- 15 of basal (n = 4), respectively. t-Boc-Phe-Leu-Phe-Leu-Phe, a competitive antagonist of formyl peptide receptor function, competitively inhibited the N-formyl-Met-Leu-Phe-induced diacylglycerol increase. Pretreatment of the cells with pertussis toxin abolished the stimulated rise in diacylglycerol, whereas depletion of extracellular Ca2+ markedly inhibited the increase. The Ca2+ ionophore A23187 stimulated a large (450% of basal) and persistent (greater than 30 min) increase in diacylglycerol. These data suggest that agents which raise intracellular Ca2+ levels in differentiated HL-60 cells produce a prolonged increase in cellular diacylglycerol which may activate protein kinase C.
D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002460:Cell Line; D004075:Diglycerides / Q000378:metabolism*; D005989:Glycerides / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D037342:Pertussis Toxin; D010586:Phagocytes / Q000378:metabolism*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D004075:Diglycerides; D005989:Glycerides; D010566:Virulence Factors, Bordetella; D000001:Calcimycin; D009240:N-Formylmethionine Leucyl-Phenylalanine; D037342:Pertussis Toxin; D002118:Calcium