The Release of Leukocytes and Platelets from the Pulmonary Circulation by Epinephrine

1. The leukocyte and platelet contents of arterial and venous blood of 12 patients were determined simultaneously during and following the intravenous administration of 0.1 to 0.3 mg. of epinephrine, l-epinephrine or norepinephrine.

2. Within 30 to 60 seconds after the start of the epinephrine administration, an initial arterial leukocytosis and thrombocytosis occurred in 10 and 8 instances respectively and continued for at least 5 minutes before it declined. A leukocytosis also occurred in the venous blood but followed the arterial rise by 30 to 120 seconds.

3. It is concluded that the initial phase of the leukocytosis and thrombocytosis following intravenous epinephrine infusion is primarily from the pulmonary circulation.

4. The data indicate that the pulmonary circulation in man is a sizable reservoir of leukocytes and platelets which may be readily discharged into the circulation under proper stimulation.