Quamme G A, Hwang P, Griesen H G, Dirks J H
Can J Physiol Pharmacol. 1976 Aug;54(4):561-76. doi: 10.1139/y76-078.
Previous studies have indicated the existence of natriuretic factors of hormonal nature with the posterior pituitary gland as a possible site of origin. It was in this light that a series of experiments was designed to examine the posterior pituitary for such factors. Acetic acid extracts of porcine and bovine posterior pituitary lobe tissue were subjected to gel filtration on Sephadex G-25. Several fractions in the molecular size range of 1000 were obtained which possessed potent natriuretic activity as assayed in rats. The activity of these fractions maximally increased sodium excretion to 6-8 muequiv./min, a 10- to 40-fold increase above control, when administered intraperitoneally to hydropenic, conscious rats. However, oxytocin and vasopressin, present in the posterior pituitary are natriuretic. These hormones were measured by radioimmunoassay, and invariably only those fractions which contained vasopressin and (or) oxytocin possessed natriuretic activity. Moreover, the extent of the natriuresis could be accounted for by the vasopressin and (or) oxytocin content of the test fractions. The natriuretic property of this material was abolished by treatment with thioglycollate. Further purification of natriuretic fractions by ion exchange resins, thin-layer chromatography and isoelectric focusing failed to resolve natriuretic activity from vasopressin and oxytocin. Similar results were observed following analysis of fractions isolated by gel filtration of acetic acid extracts of ventral hypothalamus tissue. The natriuretic fractions isolated from hypothalamic tissue were indistinguishable from oxytocin and vasopressin. These experiments suggest that the natriuretic activity in neurohypophyseal extracts can be attributed to oxytocin and vasopressin.
以往的研究表明，存在具有激素性质的利钠因子，垂体后叶可能是其起源部位。正是基于此，设计了一系列实验来检测垂体后叶中是否存在此类因子。猪和牛垂体后叶组织的醋酸提取物在葡聚糖凝胶G - 25上进行凝胶过滤。得到了几个分子大小在1000左右的组分，这些组分在大鼠实验中表现出强大的利钠活性。当将这些组分腹腔注射给缺水的清醒大鼠时，它们的活性可使钠排泄量最大增加到6 - 8微当量/分钟，比对照组增加了10至40倍。然而，垂体后叶中的催产素和加压素也有利钠作用。通过放射免疫分析法对这些激素进行测定，结果始终表明只有那些含有加压素和（或）催产素的组分才具有利钠活性。此外，利钠作用的程度可以由测试组分中加压素和（或）催产素的含量来解释。用巯基乙酸处理后，这种物质的利钠特性被消除。通过离子交换树脂、薄层色谱和等电聚焦对利钠组分进行进一步纯化，未能将利钠活性与加压素和催产素分离。对腹侧下丘脑组织醋酸提取物进行凝胶过滤分离得到的组分进行分析后，也观察到了类似的结果。从下丘脑组织中分离出的利钠组分与催产素和加压素无法区分。这些实验表明，神经垂体提取物中的利钠活性可归因于催产素和加压素。
