Redistribution of lymphocytes after cortisol administration.

Major surgical procedures awake an endocrine metabolic stress response characterized by increased secretion of cortisol and lymphopenia. The purpose of this study was to clarify to which tissues the lymphocytes are redistributed after cortisol administration. Lymphocytes were isolated from 16 rabbits, labelled with indium-111-tropolone and reinjected into the rabbits. Eight of the rabbits received 25 mg of cortisol intravenously (group I), while eight received isotonic saline (group II). The redistribution of lymphocytes was imaged with a gamma camera and calculated by a connected computer before and two, four, and seven h after cortisol or saline administration. The radioactivity of cells from the spleen and bone marrow decreased to 84% and 56% of the initial values seven h after cortisol administration. The activity of the lymphatic tissues increased to 121% of initial values. It is concluded that during cortisol-induced lymphopenia the lymphocytes are redistributed from peripheral blood, spleen and bone marrow to lymphatic tissue.