Elicitation of endotoxemic effects in C3H/HeJ mice with glucocorticoid antagonizing factor and partial characterization of the factor.

C3H/HeJ mice were used to study the origin and nature of endotoxin-induced glucocorticoid antagonizing factor (GAF). In conventional mice GAF is believed to be responsible for a variety of effects that occur as a result of an injection of endotoxin, including the inhibition of hormonal induction of hepatic phosphoenolpyruvate carboxykinase and of glyconeogenesis. Responses in such animals are seen whether the endotoxin is extracted with phenol-water or with trichloroacetic acid. C3H/HeJ mice do not respond (or produce GAF?) after an intravenous injection of phenol-water lipopolysaccharide, but they react normally (produce GAF?) when given a trichloroacetic acid preparation. They also behave the same as conventional animals when injected with serum from poisoned normal mice, especially when the reticuloendothelial system of the donors has been activated by prior injections of Zymosan or heat-killed tubercle bacilli. The C3H/HeJ mice have been used, therefore, as assay animals to establish that peak levels of GAF appear in donor serum about 2 h after an injection of lipopolysaccharide, and it is produced intraperitoneally in C3H/HeJ mice given a mixture of endotoxin and peritoneal exudate cells derived from responder mice. GAF elutes from Sephadex G-200 along with markers of known molecular weight in the region of 100,000 to 200,000. It is inactivated by trypsin and by heating at 75 degrees C for 1 h.