The differential effect of aldosterone and dexamethasone on pressor responses in adrenalectomized rats.

摘要: The effect of selective glucocorticoid or mineralocorticoid replacement on pressor responses to angiotensin I and II norepinephrine was studied in adrenalectomized rats given high salt intake. Four groups were prepared by 1) adrenalectomy only (n = 5); 2) plus aldosterone, 6 micrograms/24 hr i.p. 3) dexamethasone, 10 5), using miniosmotic pumps; 4) sham (controls; n 5). Plasma corticosterone undetectable all three groups. aldosterone concentration similar aldosterone-replaced sham-operated controls. Pressor various doses I, II, determined unanesthetized, undisturbed rats. Compared with both control dexamethasone-replaced rats, agonists significantly reduced nonreplaced Comparing the ratios four over entire dose range suggests that a greater fraction injected converted than other We conclude action markedly contributes systemic norepinephrine. However, deficiency does not impair vivo conversion II.