Whitebread S E, Taylor V, Bottari S P, Kamber B, de Gasparo M
Ciba-Geigy Ltd, Research Department, Basle, Switzerland.
Biochem Biophys Res Commun. 1991 Dec 31;181(3):1365-71. doi: 10.1016/0006-291x(91)92089-3.
CGP 42112A, a potent angiotensin AT2 receptor selective ligand, was radio-iodinated and its binding characteristics compared with those of [125I]angiotensin II. In human myometrium (only AT2 expressed), binding was saturable (Kd 1.03 x 10(-10) M; Bmax 807 fmol/mg) and reversible (K+1 1.89 x 10(8) M-1.min-1; K-1 3.77 x 10(-3) min-1). The order of potency of a number of peptides and non-peptides was the same as when [125I] angiotensin II was used as tracer. No specific binding could be detected on membranes from vascular smooth muscle cells (only AT1 expressed). In rat adrenal glomerulosa membranes (mixed AT1/AT2), [125I]CGP 42112A bound only to AT2. [125I]CGP 42112A can therefore be used as a specific probe for AT2 receptors and will be especially useful in tissues where other subtypes are also present.
强效血管紧张素AT2受体选择性配体CGP 42112A经放射性碘化处理，并将其结合特性与[125I]血管紧张素II的结合特性进行比较。在人子宫肌层（仅表达AT2）中，结合具有饱和性（解离常数Kd为1.03×10⁻¹⁰ M；最大结合量Bmax为807 fmol/mg）且可逆（正向速率常数K⁺¹为1.89×10⁸ M⁻¹·min⁻¹；逆向速率常数K⁻¹为3.77×10⁻³ min⁻¹）。许多肽类和非肽类物质的效力顺序与以[125I]血管紧张素II作为示踪剂时相同。在血管平滑肌细胞（仅表达AT1）的膜上未检测到特异性结合。在大鼠肾上腺球状带膜（AT1/AT2混合表达）中，[125I]CGP 42112A仅与AT2结合。因此，[125I]CGP 42112A可作为AT2受体的特异性探针，在同时存在其他亚型的组织中尤其有用。
