Sun Y, Weber K T
Department of Internal Medicine, University of Missouri-Columbia.
J Lab Clin Med. 1993 Oct;122(4):404-11.
Angiotensin II (AII) and mineralocorticoid receptors (MRs) have been identified in the mammalian heart and kidney. Their response to chronic elevations in circulating AII or aldosterone (ALDO) (or both) is unknown in either primary or secondary hyperaldosteronism. Nonendothelial angiotensin-converting enzyme (ACE) activity has been found in the fibrous tissue response that involves intramyocardial coronary arteries and microscopic scarring. Whether this tissue ACE could affect AII receptors and MRs in the area of myocardial fibrosis is likewise unknown. To address these questions, we monitored AII and MR binding in the rat heart and kidney after chronic AII or ALDO infusion. All receptor and MR binding were localized by in vitro autoradiography with 125I-[Sar1, Ile8]-labeled AII and [1,2,6,7 3H]-labeled ALDO, respectively. To characterize AII receptor subtypes, a type I antagonist (DuP753) or type II antagonist (PD 123177) was used. Four experimental groups were examined: unoperated, untreated, age- and sex-matched controls; age- and sex-matched uninephrectomized control rats receiving a high sodium diet; animals that received AII (9 micrograms/hr sc) for 2, 4, 6, or 8 weeks; and uninephrectomized rats on a high sodium diet that received ALDO (0.75 microgram/hr sc) for similar periods of time.(ABSTRACT TRUNCATED AT 250 WORDS)
血管紧张素II（AII）和盐皮质激素受体（MRs）已在哺乳动物的心脏和肾脏中被鉴定出来。在原发性或继发性醛固酮增多症中，它们对循环中AII或醛固酮（ALDO）（或两者）长期升高的反应尚不清楚。在涉及心肌内冠状动脉和微观瘢痕形成的纤维组织反应中发现了非内皮血管紧张素转换酶（ACE）活性。同样未知的是，这种组织ACE是否会影响心肌纤维化区域的AII受体和MRs。为了解决这些问题，我们在长期输注AII或ALDO后监测了大鼠心脏和肾脏中的AII和MR结合情况。所有受体和MR结合分别通过用125I-[Sar1，Ile8]标记的AII和[1,2,6,7 3H]标记的ALDO进行体外放射自显影来定位。为了表征AII受体亚型，使用了I型拮抗剂（DuP753）或II型拮抗剂（PD 123177）。检查了四个实验组：未手术、未治疗、年龄和性别匹配的对照组；接受高钠饮食的年龄和性别匹配的单侧肾切除对照大鼠；接受AII（9微克/小时皮下注射）2、4、6或8周的动物；以及接受高钠饮食的单侧肾切除大鼠，它们在相似的时间段内接受ALDO（0.75微克/小时皮下注射）。（摘要截短于250字）
