Regulation of prostaglandin synthesis and of the selective release of lysosomal hydrolase by mouse peritoneal macrophages

Abstract

Macrophages isolated from the peritoneal cavity of untreated mice and maintained in tissue culture synthesize and release prostaglandins when challenged with zymosan. These cells also selectively release lysosomal acid hydrolases under the same conditions. The major prostaglandins released into the media are found to be prostaglandins E1, E2 and 6-oxoprostaglandin F(1α), whereas prostaglandin F(2α) is not detected. Macrophages isolated from mice that have received an intraperitoneal injection of thioglycollate both are far less responsive to zymosan challenge. These cells require 300 μg of zymosan to synthesize and release one-third the amount of prostaglandins released from non-stimulated macrophages exposed to 50 μg of zymosan. In addition, thioglycollate-stimulated macrophages release less than 10% of their lysosomal acid hydrolases when exposed to 300 μg of zymosan whereas non-stimulated cells release approximately 50% of these enzymes after treatment with 50 μg of zymosan. The zymosan-stimulated synthesis and release of prostaglandins are completely inhibited by indomethacin, whereas the increased selective release of lysosomal acid hydrolases is not affected. Macrophages, unlike fibroblasts, do not synthesize and release prostaglandins when exposed to serum or to bradykinin.