Higelin J, Py-Lang G, Paternoster C, Ellis G J, Patel A, Dautzenberg F M
F. Hoffmann-La Roche Ltd, Pharma Division, Preclinical Research, Building 70, Room 307, Grenzacher Strasse 124, 4070, Basel, Switzerland.
Neuropharmacology. 2001;40(1):114-22. doi: 10.1016/s0028-3908(00)00105-2.
Corticotropin-releasing factor (CRF) receptors type 1 (CRF(1)) and type 2 (CRF(2)) differ from each other in their pharmacological properties. The human and ovine CRF versions bind to CRF(1) receptors with significantly higher affinity than to CRF(2) receptors. Recently antisauvagine-30, an N-terminally truncated version of the CRF analog sauvagine, was characterized as a specific antagonist to mouse CRF(2B). We have synthesized the radiolabeled version (125)I-antisauvagine-30 and tested it for its affinity at human CRF(1) (hCRF(1)), hCRF(2A), Xenopus CRF(1) (xCRF(1)) and xCRF(2) receptors. In control binding studies (125)I-labeled hCRF, sauvagine and astressin were also bound to these receptors. (125)I-antisauvagine-30 exclusively bound to hCRF(2A) and xCRF(2) but not to hCRF(1) and xCRF(1) receptors. (125)I-antisauvagine-30 binding to hCRF(2A) and xCRF(2) receptors was saturable and of high affinity (hCRF(2A): K(d)=125 pM; xCRF(2): K(d)=1.1 nM). In displacement binding experiments using (125)I-antisauvagine-30 as radioligand several CRF analogs bound to hCRF(2A) and xCRF(2) receptors with similar rank orders as reported with other CRF radioligands. Finally, preliminary studies using (125)I-antisauvagine-30 binding to membrane homogenates prepared from different rat brain structures showed that the peptide bound specifically to brain areas expressing CRF(2) receptors. These data demonstrate that (125)I-antisauvagine-30 is the first high-affinity ligand to specifically label CRF(2) receptors.
促肾上腺皮质激素释放因子（CRF）1型（CRF(1)）受体和2型（CRF(2)）受体在药理学特性上彼此不同。人类和绵羊的CRF版本与CRF(1)受体结合的亲和力显著高于与CRF(2)受体结合的亲和力。最近，抗蛙皮素-30，一种CRF类似物蛙皮素的N端截短版本，被鉴定为小鼠CRF(2B)的特异性拮抗剂。我们合成了放射性标记版本（125）I-抗蛙皮素-30，并测试了它对人类CRF(1)（hCRF(1)）、hCRF(2A)、非洲爪蟾CRF(1)（xCRF(1)）和xCRF(2)受体的亲和力。在对照结合研究中，（125）I标记的hCRF、蛙皮素和阿斯特辛也与这些受体结合。（125）I-抗蛙皮素-30仅与hCRF(2A)和xCRF(2)结合，而不与hCRF(1)和xCRF(1)受体结合。（125）I-抗蛙皮素-30与hCRF(2A)和xCRF(2)受体的结合是可饱和的且具有高亲和力（hCRF(2A)：K(d)=125 pM；xCRF(2)：K(d)=1.1 nM）。在使用（125）I-抗蛙皮素-30作为放射性配体的置换结合实验中，几种CRF类似物与hCRF(2A)和xCRF(2)受体结合的顺序与其他CRF放射性配体报道的相似。最后，使用（125）I-抗蛙皮素-30与从不同大鼠脑结构制备的膜匀浆结合的初步研究表明，该肽特异性结合表达CRF(2)受体的脑区。这些数据表明，（125）I-抗蛙皮素-30是第一个特异性标记CRF(2)受体的高亲和力配体。
