Balzan S, Montali U, Di Bartolo V, Ghione S
CNR Institute of Clinical Physiology, University of Pisa, Italy.
Life Sci. 1997;60(12):893-8. doi: 10.1016/s0024-3205(97)00020-9.
It is widely but not unanimously accepted that one or more endogenous digitalis-like factors (EDLF) circulate in human plasma. In this paper we provide confirmatory evidence that newborn plasma contains a factor with immunological and biological properties similar to ouabain and demonstrate that this factor may be present also in the adult. In fact, we obtained in newborn and adult plasma extracts, identical HPLC elution profiles of ouabain-like immunoreactivity and 86Rb erythrocyte uptake inhibitory activity with a major peak corresponding to the retention time of ouabain. The fact that immunoreactivity and biological digitalis-like activity in the peak are due to an identical substance is strongly supported by the correlation between RIA and 86Rb uptake inhibitory values observed in the purified fractions. Finally, the strong correlation between immunoreactivity observed in plasma samples after simple SepPak C18 extraction and after additional HPLC suggests that less purified samples may be assayed for screening purposes. However, for a more quantitative assessment, this simple extraction method needs a subsequent HPLC purification for eliminating an overestimation of values due to cross-reacting impurities.
人们普遍但并非一致地认为，一种或多种内源性洋地黄样因子（EDLF）在人体血浆中循环。在本文中，我们提供了确证性证据，即新生儿血浆中含有一种具有与哇巴因相似的免疫学和生物学特性的因子，并证明该因子在成年人中也可能存在。事实上，我们在新生儿和成年人血浆提取物中获得了相同的高效液相色谱（HPLC）洗脱图谱，显示出哇巴因样免疫反应性和86Rb红细胞摄取抑制活性，其主峰对应的保留时间与哇巴因一致。纯化组分中放射免疫分析（RIA）值与86Rb摄取抑制值之间的相关性有力地支持了该峰中的免疫反应性和生物学洋地黄样活性归因于同一种物质这一事实。最后，简单的SepPak C18萃取后和进一步的HPLC后血浆样品中观察到的免疫反应性之间的强相关性表明，未经充分纯化的样品可用于筛查目的的检测。然而，为了进行更定量的评估，这种简单的萃取方法需要随后进行HPLC纯化，以消除由于交叉反应杂质导致的值的高估。
