The ability of human leukocytes and platelets to generate PGE2 and PGF2α was investigated in vitro with the use of a stimulus for phagocytosis, Z(x), and the secretogogue and membrane activator, calcium ionophore A23187 (Io). Sensitive radioimmunoassays of culture supernatants for PG's were employed to quantitate production. PG's in the protein-free media were stable prior to assay and did not require extraction. Cell fractionation experiments indicated that platelets are the principal source for Io-induced PG's. Optimal Io stimulation generated 4 to 20 ng PGE/5 X 107 cells in platelet-rich cultures but < 1 ng of PGE in cultures of platelet-poor granulocytes and mononuclear cells. PG production by Io is virtually complete in < 2 min at 37°C and independent of extracellular calcium. In contrast, optimal Z(x) stimulation of similar cultures results in < 1 ng PGE/0.25 X 107 leukocytes. Z(x)-induced PG production is maximal only after 30 min at 37°C and is dependent upon extracellular calcium. All PG production by either stimulus was inhibitable by indomethacin and other nonsteroidal anti-inflammatory drugs. These studies suggest that human platelets are the richest source of PG synthetase in human blood. Io-stimulated PG production by human platelets in vitro followed by radioimmunoassay for PG's in culture supernatants provides a useful system for analysis of PG synthetase in man.
|Original language||English (US)|
|Number of pages||11|
|Journal||Journal of Laboratory and Clinical Medicine|
|State||Published - Dec 1 1977|
ASJC Scopus subject areas
- Pathology and Forensic Medicine