Cook M D, Phillips M I, Cook V I, Kimura B, Wilcox C S
Division of Nephrology, Hypertension, and Transplantation, University of Florida, Gainesville 32610.
J Am Soc Nephrol. 1993 Jul;4(1):111-6. doi: 10.1681/ASN.V41111.
Patients with an aldosterone-producing adenoma (APA) characteristically fail to show an increase in plasma aldosterone (PA) concentration with maneuvers that increase angiotensin II (Ang II), yet they retain a brisk response of PA to adrenocorticotrophic hormone. Therefore, adrenal Ang II receptor binding was characterized in a patient with APA who had a blocked PA response to Ang II infusion before adrenalectomy. The binding of [125I]Sar1,IIe5-Ang II in adrenal gland and tumor was fully displaced by excess Ang II. In the tumor, 98% of [125I]Sar1,IIe5-Ang II binding was displaced by the AT, receptor antagonist losartan, yet only 5% was displaced by the AT2 receptor antagonist PD-123,319. Autoradiography of the adrenal gland itself showed a predominance of AT1 receptors in the cortex and AT2 receptors in the medulla. The tumor showed a predominance of AT1 receptors, but there was some evidence of a limited population of AT2 receptors. The tumor and adjacent adrenal contained high concentrations of Ang II. In conclusion, a defect in Ang II-stimulated aldosterone secretion in APA occurs despite high concentrations of Ang II in the adrenal and the presence of specific, high-affinity Ang II receptor binding sites.
患有醛固酮瘤（APA）的患者在进行增加血管紧张素II（Ang II）的操作时，血浆醛固酮（PA）浓度通常不会升高，但他们对促肾上腺皮质激素的PA反应仍然活跃。因此，对一名在肾上腺切除术前对Ang II输注的PA反应受阻的APA患者的肾上腺Ang II受体结合情况进行了表征。肾上腺和肿瘤中[125I]Sar1,IIe5-Ang II的结合被过量的Ang II完全取代。在肿瘤中，98%的[125I]Sar1,IIe5-Ang II结合被AT1受体拮抗剂氯沙坦取代，但只有5%被AT2受体拮抗剂PD-123,319取代。肾上腺自身的放射自显影显示，皮质中以AT1受体为主，髓质中以AT2受体为主。肿瘤以AT1受体为主，但有一些证据表明存在有限数量的AT2受体。肿瘤和相邻的肾上腺含有高浓度的Ang II。总之，尽管肾上腺中Ang II浓度很高且存在特异性、高亲和力的Ang II受体结合位点，但APA中Ang II刺激的醛固酮分泌仍存在缺陷。
