Vandekerckhove A, Keppens S, De Wulf H
Afdeling Biochemie, Fakulteit Geneeskunde, Katholieke Universiteit Leuven, Belgium.
J Endocrinol. 1989 Oct;123(1):131-6. doi: 10.1677/joe.0.1230131.
A homologous population of specific angiotensin II receptors is present on the cell surface of isolated rabbit hepatocytes. The binding characteristics of [3H]angiotensin II to the cells were: association rate constant (K+1) 0.08 l/nmol per min and dissociation rate constant (K-1) 1.9/min, yielding a dissociation constant (Kd) of 24 nmol/l. A very similar Kd (32 nmol/l) has been derived from saturation binding data which indicate a maximal binding capacity of about 200,000 sites/cell. Analysis of the association binding data to purified liver plasma membranes indicated a Kd of 6 nmol/l in the absence and 30 nmol/l in the presence of GTP. Dissociation was clearly dependent upon the presence of the nucleotide, which shifted the K-1 from 0.12/min to 0.42/min. The studied binding sites are very likely to be involved in the glycogenolytic action of angiotensin II, since a highly significant correlation was established between the biological activity (activation of glycogen phosphorylase) and the binding affinity of a series of agonistic analogues. The reported characteristics of the rabbit hepatic angiotensin II receptors show much similarity with those of rat liver.
在分离的兔肝细胞表面存在特定血管紧张素II受体的同源群体。[3H]血管紧张素II与细胞的结合特性为：结合速率常数（K+1）0.08 l/（nmol·min），解离速率常数（K-1）1.9/min，解离常数（Kd）为24 nmol/l。从饱和结合数据得出的Kd（32 nmol/l）非常相似，这表明最大结合容量约为200,000个位点/细胞。对纯化肝细胞膜的结合数据进行分析表明，在不存在GTP时Kd为6 nmol/l，存在GTP时为30 nmol/l。解离明显依赖于核苷酸的存在，这使K-1从0.12/min变为0.42/min。所研究的结合位点很可能参与血管紧张素II的糖原分解作用，因为在生物活性（糖原磷酸化酶的激活）与一系列激动剂类似物的结合亲和力之间建立了高度显著的相关性。所报道的兔肝血管紧张素II受体的特性与大鼠肝脏的特性非常相似。
