Yasuda N, Yasuda Y
Fed Proc. 1985 Jan;44(1 Pt 2):183-8.
Corticotropin-releasing factor B (CRF-B) is a peptide(s) isolated from bovine hypothalamic extracts by Sephadex G-100 chromatography on the basis of its ability to stimulate secretion of adrenocorticotropin (ACTH) in vitro and in vivo. It is similar in molecular size to the 41-residue ovine CRF (oCRF) or rat CRF (rCRF) recently elucidated and appears to be their bovine counterpart. Immunoreactivity of CRF-B was examined in homologous radioimmunoassays (RIAs) for oCRF or rCRF, using several anti-oCRF and anti-rCRF antibodies. CRF-B cross-reacted well with anti-oCRF antibodies but poorly with anti-rCRF antibodies. Purification of CRF-B with preparative isoelectric focusing yielded four CRF peaks, B-1 (pH 4.7), B-2 (pH 5.5), B-3 (pH 6.3), and B-4 (pH 7.0), which accounted for 16, 30, 46, and 8% of the total immunoreactivity, respectively. CRF B-2, B-3, and B-4 showed both immunological activity and biological activity in vitro (cell culture assay) and in vivo (Arimura assay), whereas CRF B-1 showed only immunoreactivity. Their relative bioactivity/immunoreactivity ratios were 0 (B-1), 1 (B-2), 1 (B-3), and 3 (B-4). All of these CRF-B subtypes exhibited RIA displacement curves parallel to that for the oCRF standard and coeluted with oCRF on Sephadex G-100 chromatography, which suggests that their molecular modifications are relatively minor.
促肾上腺皮质激素释放因子B（CRF-B）是一种通过Sephadex G-100层析从牛下丘脑提取物中分离出的肽，基于其在体内外刺激促肾上腺皮质激素（ACTH）分泌的能力。它在分子大小上与最近阐明的41个氨基酸残基的绵羊CRF（oCRF）或大鼠CRF（rCRF）相似，似乎是它们的牛对应物。使用几种抗oCRF和抗rCRF抗体，在针对oCRF或rCRF的同源放射免疫分析（RIA）中检测了CRF-B的免疫反应性。CRF-B与抗oCRF抗体交叉反应良好，但与抗rCRF抗体交叉反应较差。用制备性等电聚焦纯化CRF-B产生了四个CRF峰，B-1（pH 4.7）、B-2（pH 5.5）、B-3（pH 6.3）和B-4（pH 7.0），它们分别占总免疫反应性的16%、30%、46%和8%。CRF B-2、B-3和B-4在体外（细胞培养分析）和体内（有村分析）均显示出免疫活性和生物活性，而CRF B-1仅显示免疫反应性。它们的相对生物活性/免疫反应性比率分别为0（B-1）、1（B-2）、1（B-3）和3（B-4）。所有这些CRF-B亚型的RIA置换曲线与oCRF标准品的曲线平行，并且在Sephadex G-100层析上与oCRF共洗脱，这表明它们的分子修饰相对较小。
