The use of Reuber hepatoma cells for the study of a lipopolysaccharide-induced macrophage factor: glucocorticoid-antagonizing factor.
Endotoxin-stimulated glucocorticoid-antagonizing factor (GAF) was assayed by its specific inhibition of hydrocortisone-induced synthesis of phosphoenolpyruvate carboxykinase. Defined induction of phosphoenolpyruvate carboxykinase synthesis in hydrocortisone-treated rat hepatoma cells permitted reliable quantitation of GAF and analysis of the mechanism of cortisol antagonism. GAF was present maximally in serum 2 hours after endotoxin challenge in mice; however, GAF production could be suppressed by pretreating mice with indomethacin or cortisol. Endotoxin-tolerant mice were also nonresponsive to endotoxin-stimulated GAF production. Gel filtration on Sephadex G-200 resolved four regions of glucocorticoid-antagonizing activity in serum from endotoxin-poisoned mice, two of which were not present in normal serum. Cortisol antagonism by GAF resembled that of insulin; however, insulin differed from GAF in its ability to antagonize dibutyryl cyclic AMP. Unlike insulin, endotoxin-induced serum glucocorticoid-antagonizing activity was heat-labile at 70 degrees C. GAF antagonism of hydrocortisone was partially reversible but did not act in a competitive manner. Production of hepatoma growth inhibitory activity and glucocorticoid-antagonizing activity in serum were closely associated, indicating a common methanism for their generation.
D000818:Animals; D001798:Blood Proteins / Q000096:biosynthesis*; D002460:Cell Line; D004731:Endotoxins; D004790:Enzyme Induction; D005938:Glucocorticoids / Q000037:antagonists & inhibitors*; D006854:Hydrocortisone / Q000037:antagonists & inhibitors / Q000494:pharmacology; D007213:Indomethacin / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000096:biosynthesis
D001798:Blood Proteins; D004731:Endotoxins; D005938:Glucocorticoids; D007328:Insulin; D010729:Phosphoenolpyruvate Carboxykinase (GTP); D006854:Hydrocortisone; D007213:Indomethacin