Benveniste R, Warshaw M L, Frohman L A, Reagan C R, Kostyo J L
Biochim Biophys Acta. 1977 Mar 29;497(1):307-16. doi: 10.1016/0304-4165(77)90164-7.
In an attempt to search for growth hormone fragments in the pituitary, a radioimmunoassay was developed for a 55 residue S-amino-ethylated CNBr fragment (fragment B) of porcine growth hormone corresponding to residues 126-180 of human growth hormone. The assay was sensitive to 50 pg of fragment B whereas displacement of 125I-labelled fragment B by procine growth hormone required a 10(3) M excess and was non-parallel. In a homogolous porcine growth hormone radioimmunoassay, fragment B was non-reactive. Gel filtration of an extract of porcine pituitary on Sephadex G-75 revealed three peaks of fragment B immunoreactivity: peak I (29% of total immunoreactivity) eluted in the void volume, peak II (49%) eluted in the position of growth hormone, and peak III (12%) was more retarded than fragment B. Nearly all of the growth hormone immunoreactivity eluted as a single peak in the position of 125I-labelled porcine growth hormone. The dilution curve of peak III but not of peaks I or II was parallel to that of fragment B. The results indicate the existence within porcine pituitary of material cross-reactive with a portion of the growth hormone molecule, possible representing a growth hormone fragment.
为了在垂体中寻找生长激素片段，开发了一种放射免疫分析法，用于检测猪生长激素的一个含55个残基的S-氨乙基化溴化氰片段（片段B），该片段对应于人生长激素的第126 - 180位残基。该分析法对50 pg的片段B敏感，而猪生长激素对125I标记的片段B的置换需要10(3) M的过量，且不呈平行关系。在同源的猪生长激素放射免疫分析法中，片段B无反应性。用Sephadex G - 75对猪垂体提取物进行凝胶过滤，发现有三个片段B免疫反应性峰：峰I（占总免疫反应性的29%）在空体积处洗脱，峰II（49%）在生长激素的位置洗脱，峰III（12%）比片段B洗脱得更慢。几乎所有的生长激素免疫反应性都作为一个单一峰在125I标记的猪生长激素的位置洗脱。峰III的稀释曲线与片段B的平行，而峰I和峰II的不平行。结果表明猪垂体中存在与生长激素分子一部分有交叉反应的物质，可能代表一种生长激素片段。
