Interaction between Hormones and the Immune System

Abstract

After a short introduction into the general topic, the catecholamine-induced increase of leukocytes in which the granulocytes are predominant after short-term exercise is discussed. The reduction of lymphocytes is associated with work-dependent cortisol increase after long-term exercise or 1 h after strenuous work. The catecholamine-stimulated lymphocytes increase could be explained by the liberation of the cells from the endothelial vessel wall after catecholamine interaction with the ß-adrenoceptors and by mobilization from lymph nodes and spleen after ß-adrenergic stimulation. Catecholamines reduce the proliferation of lymphocytes and the degranulation of mast cells, preventing hypersensitivity reaction due to inhibited mediator liberation. The influence of cortisol and cytokines and vice versa is discussed. The hormonal changes after runs of different intensities and duration are demonstrated; they show an interaction with immunological regulation. The neuroimmune modulation after physical and psychological stress also has to be considered in immune regulation since under this condition the secretion of encephalins, endorphins, ACTH, and cortisol is increased. The significance of enhanced vasopressin secretion causing postural fainting by vagovasal reaction indicates also the effect of a neuropeptide which is related to immunological reactions. In the changes of lymphocyte subclasses, the homing effect of these cells should be regarded. Advices which can improve the immunologic behaviour, avoiding susceptibility to infections by well-conducted training regimens and adequate periods of regeneration time, are necessary. The multifold mechanisms involved in the immune regulation and the interaction with several hormonal and metabolic changes caused by exercise make it diffucult to give, at the present time, well-founded practical pieces of advice; it needs more work and well-conducted studies of exercise and competition.

Key words

Hormonal immunologic modulation - leukocytes - lymphocytes - catecholamines - cortisol - neuropeptides - cytokines - lymphocytes subpopulation