Rat model for investigating ACTH-independent angiotensin-induced aldosterone secretion

Study of the acute effects of angiotensin II (Ang II) on aldosterone secretion has been hindered by the confounding influence of Ang II-induced adrenocorticotropic hormone (ACTH) secretion on aldosterone secretion, and by the fact that when laboratory rats are fed standard laboratory chows that are high in sodium, the adrenal is only minimally responsive to Ang II. In this study, we report the development of a model of Ang II-induced aldosterone secretion in NaCl-deprived, dexamethasone (DEX)-treated rats. This model allows the observation of (a) a high magnitude of Ang II-induced aldosterone secretion, (b) a return of plasma aldosterone levels to baseline after stimulation, and (c) aldosterone secretion without the potentially confounding influence of ACTH stimulation.