Fibrinogen levels after inflammation or endotoxin in normal and hypophysectomized rats.

The hypothesis that pituitary hormones are required for increased fibrinogen synthesis after inflammation or endotoxin was tested by measuring plasma fibrinogen concentrations after inflammation or endotoxin in normal and hypophysectomized rats. Animals were divide into groups receiving no exogenous adrenal steroids, low-dose adrenal steroids, or high-dose adrenal steroids. Hypophysectomy failed to prevent fibrinogen levels from rising after intramuscular turpentine (mean 240 mg/100 ml prior to and 556 mg/100 ml 24 h after turpentine). Steroids did not suppress this rise. Endotoxin, 5 mug/100 g, caused a marked rise in fibrinogen in normal rats at 24 h (mean 296 mg/100 ml before endotoxin and 554 mg/100 ml after endotoxin). This dose of endotoxin killed hypophysectomized rats within 12 h. Hoevr, if hypophysectomized rats were protected with high-dose adrenal steroids, then 5 mug of endotoxin per 100 g caused the same fibrinogen rise as in normal rats (mean 299 mg/100 ml before endotoxin and 587 mg/100 ml after endotoxin). Aparently, pituitary hormones are not necessay for increased fibrinogen synthesis after either inflammation or endotoxin in the rat.