The Permissive Role of Cortisol

From the above outline of some of the endocrine changes consequent on physical injury, including the discussion of thyroid activity in Section 

the overriding impression which one has is that of a blanket stimulation of endocrine secretions. 

Apart from catecholamine secretion, it is not obvious what role increased endocrine activity would have in homeostasis after injury. In adrenalectomized dogs subjected to hemorrhagic injury, cortisol and aldosterone will each cause an expansion of extracellular fluid volume by mobilization of cell water within 6 hours of administration. Cortisol, but not aldosterone, also will cause an expansion of plasma volume which can be attributed to its effects on the peripheral vasculature. Spironolactone will prevent the shift of water from the body cell mass to the interstitial fluid (M3). The above experimental evidence clearly im- 

The role of the adrenal gland in various responses to various stresses has been widely studied. John (Jl) found that sound stress for a period of 1.5 hours produced marked lymphocytopenia in normal but not adre-nalectomized rats. Estimating the normal daily in vivo production of corticoid to be equivalent to 0.8 j ,g of cortisone acetate per kilogram body weight injected subcutaneously as an aqueous suspension, Johns noted that injection of 4.0 mg of cortisone acetate per 100 g body weight into adrenalectomized rats resulted in lymphocytopenia. Injection of doses of cortisone acetate more equivalent to the normal daily secretion of corticoid in intact animals did not produce lymphocytopenia in adrenalectomized rats, but did restore the lymphocytopenic response to sound stress. 

Weimer and colleagues have studied the response of the a -acute phase globulins of rat serum to trauma, and the interaction of adrenal function with this response (W7-W9). 

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