Adrenal 11-beta hydroxysteroid dehydrogenase activity in response to stress

Abstract

This work studied the effect of stresses produced by simulated gavage or gavage with 200 mmol/L HCl two hours before adrenal extraction, on the activities of the 11β-hydroxysteroid dehydrogenase 1 and 11β-hydroxysteroid dehydrogenase 2 isoforms present in the rat adrenal gland. These activities were determined on immediately prepared adrenal microsomes following incubations with3H-corticosterone and NAD+or NADP+. 11-dehydrocorticosterone was measured as an end-product by TLC, and controls were adrenal microsomes from rats kept under basal (unstressed) conditions. 11β-hydroxysteroid dehydrogenase 1 activity, but not 11β-hydroxysteroid dehydrogenase 2 activity, was increased under both stress-conditions. Homeostatically, the stimulation of 11β-hydroxysteroid dehydrogenase 1 activity would increase the supply of glucocorticoids. These, in turn, would activate the enzyme phenylethanolamine N-methyl transferase, thereby improving the synthesis of epinephrine as part of the stress-response.Key words: acidosis, adrenal, HSD, stress.