The effect of suppressive doses of glucocorticoids on aldosterone secretion was studied.
Dexamethasone in a dose of 2 mg/day for two
days resulted in a 38% decrease in aldosterone
secretory rate (ASR) in 18 of 22 patients studied.
Three of the four patients who showed no decrease in ASR had primary aldosteronism.
Angiotensin infusion increased ASR before and
after dexamethasone suppression, but the rise in
ASR after combined dexamethasone suppression
and angiotensin infusion was still 30% less than
the control-unstimulated ASR. Sensitivity to
endogenously generated angiotensin was similarly
blunted by dexamethasone suppression. It is
concluded that suppression of endogenous adrenocorticotropic activity significantly reduces
the adrenal secretory response to angiotensin.