Relation between cardiovascular diseases and cardiac hormones

心脏是一个泵血器官；然而，它可能在心力衰竭中产生许多激素。尤其是ANP和BNP的大量合成。我们最近的研究表明，各种类固醇激素也是用非常少的量合成的。另一方面，类固醇激素在心脏中的作用也可能超出传统观念。在这项研究中，我们发现醛固酮具有抗细胞脱水的作用；Na^+/H^+交换剂1 （NHE1）在其中起着重要的作用。通过使Na^+流入细胞，防止了细胞在高渗透压下的收缩。然而，当这一过程持续较长时间后，细胞内Ca^<2+>浓度升高导致心肌肥厚。在临床方面，我们推进了心力衰竭的医学治疗研究。虽然肾素-血管紧张素系统的抑制药物和抗醛固酮药物是必不可少的，但钾浓度过高是一个重要的问题。我们以1035例住院患者为研究对象，详细考察了哪些因素会影响钾离子浓度。因此，尽管肾功能不全、糖尿病和RAA系统抑制药物的使用使钾浓度升高，但在心力衰竭状态下钾浓度反而降低。这与传统的研究结果相反；因此，需要进一步的论证。另一方面，虽然hANP在急性心力衰竭中应用较多，但其作用机制尚不清楚。在本研究中，我们将心力衰竭患者分为两组；hANP治疗组和呋塞米治疗组。虽然血液动力学参数的改善几乎相似，但氧化应激的改善在hANP组明显更大。这一作用也将在培养的新生大鼠心肌细胞实验中得到证实，其机制的阐明是一个未来的课题。

The heart is a pump organ; however, it might produce many hormones in heart failure. Especially ANP and BNP are synthesized in large quantities. We have recently shown that various kinds of steroid hormone are also synthesized with a very small quantity. On the other hand, the action of steroid hormones in the heart may also exceed the conventional concept. In this study, we found that aldosterone has an action for anti-cellular dehydration; Na^+/H^+ exchanger 1 (NHE1) plays an important role there deeply. Cell shrinkage under high osmolarity was prevented by making Na^+ flow into the cell. However, when this became a long period, the rise of intracellular Ca^<2+> concentration leaded to cardiac hypertrophy.From the clinical side, we advanced researches on the medical treatment of heart failure. Although the inhibitory drugs of the renin-angiotensin system and anti-aldosterone agents are indispensable, too much rise of the potassium concentration is an important problem. We examined in detail what kind of factors would influence the potassium concentration by using 1,035 patients admitted to our institution. As a result, although renal insufficiency, diabetes, and use of the inhibitory drugs of the RAA system raised the potassium concentration, it was reduced rather in heart failure status. This is contrary to the conventional research findings; and thus the further argument is needed. On the other hand, although hANP is used more often in acute heart failure, there are still unknown mechanisms. In this study, we divided the heart failure patients into two groups; hANP treatment group and furosemide treatment group. Although the improvement of hemodynamic parameters were almost similar, the improvement of oxidative stress was significantly lager in the hANP group. This action will be confirmed also in the experiment using cultured neonatal rat cardiomyocyte, and the elucidation of that mechanism is a future subject.