King J A, Millar R P
Endocrinology. 1979 Dec;105(6):1322-9. doi: 10.1210/endo-105-6-1322.
Immunoreactive GH release-inhibiting factor [somatostatin (SRIF)] was detected in hypothalamus, extrahypothalamic brain, pancreas, and stomach extracts of the rat, pigeon, tortoise, frog, teleost (cichlid), and elasmobranch (dogfish) and in the whole brain of the cyclostome (hagfish). The SRIF concentration was higher in the pancreas and gastrointestinal tract than in the hypothalamus and extrahypothalamic brain in most species. Extracts of the various tissues from the different species assayed in serial dilutions gave displacement curves parallel to those of synthetic mammalian SRIF. Cation exchange chromatography of hypothalamic extracts from the various species revealed two major immunoreactive peaks, one of which correpsonds to synthetic SRIF in elution volume, the other being less basic. Affinity chromatography-purified immunoreactive SRIF from frog brain, pancreas, and stomach extracts coeluted with synthetic SRIF in high pressure liquid chromatography. The results indicate that immunoreactive SRIF in various tissues and in different vertebrates is indistinguishable and suggest that there has been no change in the molecule during at least 400 million yr of evolution.
在大鼠、鸽子、乌龟、青蛙、硬骨鱼（丽鱼科）和软骨鱼（角鲨）的下丘脑、下丘脑外脑区、胰腺和胃提取物中，以及圆口纲动物（盲鳗）的全脑中检测到了免疫反应性生长激素释放抑制因子[生长抑素（SRIF）]。在大多数物种中，胰腺和胃肠道中的SRIF浓度高于下丘脑和下丘脑外脑区。对不同物种的各种组织提取物进行系列稀释测定，得到的置换曲线与合成的哺乳动物SRIF的曲线平行。对不同物种下丘脑提取物进行阳离子交换色谱分析，发现有两个主要的免疫反应峰，其中一个在洗脱体积上与合成SRIF相对应，另一个碱性较弱。从青蛙脑、胰腺和胃提取物中经亲和色谱纯化的免疫反应性SRIF在高压液相色谱中与合成SRIF共洗脱。结果表明，不同组织和不同脊椎动物中的免疫反应性SRIF无法区分，这表明在至少4亿年的进化过程中，该分子没有发生变化。
