Author: LA Hedman ( )
The influence of stress on the circulating lymphocyte population in rats was studied at different times after stress stimuli and correlated to the concentration of corticosterone in serum. A rapid increase of the corticosterone level, with a duration of about one hour, was seen in both normal and thymectomized animals. Female rats showed higher serum levels than male rats. Depression of thoracic duct lymphocyte cell levels in normal animals seemed to be maximal about 3 hours after exposure to stress and restitution to pretreatment levels was completed within 1- 2 days. The lymph cell population in neonatally thymectomized animals did not show any significant changes after stress.
The endogenous corticosterone secretion after stress gave the same changes in the circulating lymphocyte population in normal rats as after injection of a high dose of prednisolone. Because of the absence of effect on thymectomized animals, the effect of endogenous secreted corticosteroids seems to be mainly on T-lymphocytes. The findings suggest the existence of a circulating highly steroid-sensitive thymus-dependent lymphocyte population. This population seems normally to be depressed by stress mechanisms mediated by adrenal corticosteroid secretion. There also seems to be a difference between circulating T- and B-lymphocytes with respect to sensitivity to low doses of naturally secreted corticosteroids.
Keywords: Lymphocyte, Thoracic duct, Blood, Stress, Rat, Thymectomy, Corticosterone
How to Cite: Hedman, L. (1980) “THE EFFECT OF STEROIDS ON THE CIRCULATING LYMPHOCYTE POPULATION”, Lymphology. 13(1).