The Role of Inositol Phospholipid Metabolism and Diacylglycerol Production in Neutrophil Signal Transduction *

In 1953 M. R. Hokin and L. E. Hokin discovered that receptor-mediated activation of cells led to the stimulation of phospholipid metabolism. Neutrophils are no exception in that cell-surface stimulation also leads to enhanced turnover of phospholipids. It is only in the function of stimulated phospholipid metabolism has been elucidated due to the recent observations that diacylglycerol is an activator of a Ca²⁺ and phospholipid dependent protein kinase and inositol 1,4,5- trisphosphate is responsible for mobilizing Ca²⁺ from intracellular stores. Neutrophils from a variety of sources have been used in the study of receptor-mediated inositol lipid metabolism. Most studies have utilized either human neutrophils from peripheral blood or rabbit and guinea pig neutrophils that have been elicited by injection of glycogen or casein into the peritoneum. Cytochalasin B, a fungal metabolite, has been widely used because it potentiates the response of the neutrophil to soluble agonists.