Rabey Felicia M, Karamyan Vardan T, Speth Robert C
Department of Pharmacology, School of Pharmacy, University of Mississippi, University, MS 38677, USA.
Regul Pept. 2010 Jun 8;162(1-3):5-11. doi: 10.1016/j.regpep.2010.02.007. Epub 2010 Feb 19.
A novel binding site for angiotensins II and III that is unmasked by parachloromercuribenzoate has been reported in rat, mouse and human brains. Initial studies of this binding site indicate that it is not expressed in the adrenal, liver or kidney of the rat and mouse. To determine if this binding site occurs in other mouse tissues, 8 tissues were assayed for expression of this binding site by radioligand binding assay and compared with the expression of this binding site in the forebrain. Particulate fractions of homogenates of testis, epididymis, seminal vesicles, heart, spleen, pancreas, lung, skeletal muscle, and forebrain were incubated with (125)I-sarcosine(1), isoleucine(8) angiotensin II in the presence or absence of 0.3mM parachloromercuribenzoate plus 10microM losartan and 10microM PD123319 (to saturate AT(1) and AT(2) receptors). Specific (3microM angiotensin II displaceable) high affinity binding occurred in the testis>forebrain>epididymis>spleen>pancreas>lung when parachloromercuribenzoate was present. Binding could not be reliably observed in heart, skeletal muscle and seminal vesicles. High affinity binding of (125)I-sarcosine(1), isoleucine(8) angiotensin II was observed in the absence of parachloromercuribenzoate in the pancreas on occasion. This suggests that this novel angiotensin binding site may have a functional role in these tissues.
在大鼠、小鼠和人类大脑中，已报道一种被对氯汞苯甲酸暴露的血管紧张素II和III的新型结合位点。对该结合位点的初步研究表明，它在大鼠和小鼠的肾上腺、肝脏或肾脏中不表达。为了确定该结合位点是否存在于其他小鼠组织中，通过放射性配体结合试验检测了8种组织中该结合位点的表达，并与前脑中该结合位点的表达进行了比较。将睾丸、附睾、精囊、心脏、脾脏、胰腺、肺、骨骼肌和前脑匀浆的微粒体部分与（125）I-肌氨酸（1）、异亮氨酸（8）血管紧张素II在存在或不存在0.3mM对氯汞苯甲酸加10μM氯沙坦和10μM PD123319（以饱和AT（1）和AT（2）受体）的情况下孵育。当存在对氯汞苯甲酸时，特异性（3μM血管紧张素II可置换）高亲和力结合发生在睾丸>前脑>附睾>脾脏>胰腺>肺中。在心脏、骨骼肌和精囊中未可靠观察到结合。偶尔在胰腺中，在不存在对氯汞苯甲酸的情况下观察到（125）I-肌氨酸（1）、异亮氨酸（8）血管紧张素II的高亲和力结合。这表明这种新型血管紧张素结合位点可能在这些组织中具有功能作用。
