FUNDAMENTAL STUDIES ON THE HYPOTHALAMIC DIGITALIS-LIKE SUBSTANCE

内源性洋地黄样物质（EDLF）释放机制：脑室内注入高渗生理盐水，血浆地高辛样免疫反应性（DLI）水平升高。在本研究中，我们发现静脉输注生理盐水导致血浆DLI升高。高渗盐水对生理盐水没有额外的影响。因此，钠的中枢作用可能是一种机制，而中心静脉压升高可能是另一种机制。在慢性钠负荷情况下，钠可能影响中枢神经系统释放DLI，因为脑脊液中的钠浓度随着钠负荷的增加而升高。免疫组化研究：用抗地高辛抗体检查脑组织时，我们发现DLI存在于室旁核和视上核的细胞体中，其纤维分布于OVLT、SFO等脑室周围器官和正中隆起。一些含有更多DLI的细胞也含有加压素和/或催产素。在垂体后叶也有发现。肾小管上皮细胞有微弱的免疫反应。EDLF与胰岛素抵抗的关系：胰岛素抵抗是高血压、糖尿病、高脂血症和动脉粥样硬化的发病机制。由于胰岛素增加了肾脏钠的吸收，我们认为EDLF的增加可能是高血压的原因。结果表明，血清胰岛素水平不仅与血压显著相关，而且与血浆DLI浓度显著相关。经与血压的多元回归分析计算胰岛素的偏F比，在交界组最大，在糖尿病组未达到显著水平。结论：当胰岛素水平升高并促进钠重吸收时，EDLF从下丘脑释放，特别是在交界性糖尿病组。在糖尿病组中，除了胰岛素之外，还有其他机制导致血压升高。少

Mechanism of Releases of Endogenous Digitalis-like Substance(EDLF):When hypertonic saline was infused intracerebroventricularly, the plasma level of digoxin-like immunoreactivity (DLI) elevates. In the present study, we found that intravenous infusions of saline caused elavation of plasma DLI. Hypertonic saline did not have additional effects on the regular saline. Therefore, the central effects of sodium could be one of mechanisms, and the elevation of central venous pressure could be the other. On the chronic condition of sodium-loading, however, sodium may affect the central nervous system to release the DLI since sodium concentration in the cerebrospinal fluid elevates with the sodium-loading.Immunohistochemical Study:When the brain tissue was examined with anti-digoxin antibody, we found that the DLI exists in the cell body of the paraventricular and supraoptic nuclei, and their fibers distributed in the periventricular organs such as OVLT and SFO, and median eminence. Some of the … More DLI containing cells also contained vasopressin and/or oxytocin. It was also found in the posterior pituitary. In the Kidneys, the faint immunoreactivity was found at the tubular epithelial cells.Relationship Between EDLF and Insulin Resistance: The interest has been focussed on the insulin resistance as the pathogenesis of hypertension, diabetes, hyperlipidemia and atherosclerosis. Because insulin increases renal sodium absorption, we thought that EDLF may be increased as the cause of hypertension. As the results, serum insulin levels significanty correlated not only with blood pressure, but also with plasma DLI concentrations. When the partial F ratio of insulin was calculated with a multiple regression analysis against blood pressure, it was the greatest in the borderline group, and was not achieve the significant level in a diabetic group.Conclusion: When insulin levels are elevated and promoted sodium reabsorption, EDLF is released from the hypothalamus particularly in the borderline diabetic group. In the diabetic group, other mechanisms than insulin is responsible for the elevation of blood pressure. Less