Effects of corticosteroid treatment and inflammation on the cellular content of blood and exudate in mice

Inflammatory exudates have been produced in mice by intraperitoneal injection of thioglycollate broth 24 hr and again 3 hr before collecting of the exudate. The first injection of broth exerts a "priming" effect leading to an enhanced response to the second injection. By this procedure more than 30 x 106 leucocytes of which 78 per cent. were polymorphs were obtained from each mouse. Administration of paramethasone reduced the number of cells in the exudate when given at the same time as broth but not when given 3 hr before collection of the exudate. In contrast paramethasone was equally effective when given either 24 hr or 3 hr before harvest in suppressing the appearance of intravenously injected pontamine sky blue in the exudate. It was striking that treatment with paramethasone which had reduced the number of polymorphs in the exudate had actually increased the number in blood.