Tahara Y, Shima K, Hirota M, Ikegami H, Tanaka A, Kumahara Y
Biochem Biophys Res Commun. 1983 May 31;113(1):340-7. doi: 10.1016/0006-291x(83)90471-0.
A high level of glucagon immunoreactivity was apparently detected in acid-saline extract from rat submandibular glands, but tracer glucagon added to the assay mixture was mostly damaged in spite of the presence of protease inhibitors commonly used in radioimmunoassay. Gel-filtration of the extract on a Bio-Gel P-10 column revealed strong tracer-degrading activity at the void fraction where the apparent immunoreactivity was eluted. Serial changes in apparent immunoreactivity of the extract fit well on the theoretical curve of an exponential tracer degradation. These findings indicate that the salivary gland glucagon is a fictitious substance due to tracer degradation during radioimmunoassay. Further study revealed that the glucagon molecule was hydrolyzed at the arginyl bonds and split into two fragments during incubation with the acid-saline extract from rat submandibular glands.
在大鼠颌下腺的酸 - 盐提取物中明显检测到高水平的胰高血糖素免疫反应性，但尽管放射免疫测定中常用蛋白酶抑制剂存在，添加到测定混合物中的示踪胰高血糖素大多被破坏。提取物在Bio - Gel P - 10柱上进行凝胶过滤，在洗脱明显免疫反应性的空体积部分显示出强烈的示踪剂降解活性。提取物表观免疫反应性的系列变化与指数示踪剂降解的理论曲线拟合良好。这些发现表明，由于放射免疫测定过程中的示踪剂降解，唾液腺胰高血糖素是一种虚拟物质。进一步研究表明，胰高血糖素分子在与大鼠颌下腺的酸 - 盐提取物孵育期间在精氨酰键处被水解并分裂成两个片段。
