Studies on Adrenaline-induced Leucocytosis in Normal Man

S ummary . Adrenaline-induced peripheral blood leucocytosis has been studied in three healthy normal and three healthy splenectomized males. An indwelling venous cannula allowed very frequent samples to be obtained before and after intramuscular injection of 1 mg adrenaline. It is confirmed that within the first 30 min there is a predominant lymphocytosis. Thereafter there is a variable neutrophilia with relative lymphopenia. Evidence was found for more than one peak in the early lymphocytosis. We have failed to find the mechanisms which are involved in leucocyte mobilization. Contraction of the spleen appears to play no significant part. In two experiments, sampling of blood simultaneously from the left innominate and right brachial veins yielded no evidence for a major additional influx of lymphocytes into the circulation via the thoracic duct in response to adrenaline.