Leukotriene B4 and C4 production in isolated rat gastric mucosal cells

Dispersed rat gastric mucosal cells (F0) were separated into five fractions (F1-F5) by counterflow elutriation, with F1 representing the smallest and F5 the largest cell diameters. In F0-F5, leukotriene B4 (LTB4) release in response to 10(-5) M calcium ionophore A-23187 was 7.68 +/- 1.26, 51.6 +/- 10.8, 72.4 +/- 10.4, 7.1 +/- 0.7, 5.7 +/- 0.6, and 11.6 +/- 3.4 pg.10(6) cells-1 x 30 min-1. In the identical fractions, sulfidopeptide release in response to A-23187 was 200.6 +/- 20.5, 1,116.0 +/- 166.6, 1,309.4 +/- 163.2, 189.8 +/- 25.8, 108.0 +/- 18.0, and 158.4 +/- 54.0 pg.10(6) cells-1 x 30 min-1. High-pressure liquid chromatography verified the radioimmunologically determined LTB4 and identified LTC4 as the only sulfidopeptide LT released. LT release from F2 cells in response to A-23187 was time and dose dependent, reaching maximal stimulation at 10(-5) M A-23187. This response was blocked by the dual inhibitor of cyclooxygenase and lipoxygenases, BW755C (2 x 10(-5)-2 x 10(-4) M), by the selective 5-lipoxygenase inhibitor L-651,392 (10(-7)-10(-5) M), and by MK-886 (10(-9)-10(-7) M), which blocks translocation of 5-lipoxygenase. The postreceptor stimuli dibutyryl adenosine 3',5'-cyclic monophosphate, forskolin, 12-O-tetradecanoyl-phorbol-13-acetate, and oleyl-acetyl-glycerol failed to induce LT release. However, 10(-4) M arachidonic acid increased basal LT release up to eightfold and increased A-23187-stimulated LT release by an additional 30%.(ABSTRACT TRUNCATED AT 250 WORDS)