Quiescent mouse peritoneal macrophages which phagocytose, and which respond to phagocytosis with a sudden elevation in hexose monophosphate shunt activity, immediately release into the medium oxygen metabolites, arachidonic acid oxygenation products, and lysosomal hydrolases. Such cells subsequently differentiate and acquire the properties of inflammatory macrophages. The latter process appears to be under the control of prostaglandin E 2 and possibly other cyclooxygenase products which are formed as a consequence of phagocytosis and seem to act as feed-back inhibitors.
