Uroguanylin in the pathophysiological mechanism in water and electrolyte homeostoses

尿鸟苷是一种最初从尿液中分离出来的新的利钠肽，它刺激细胞膜上的鸟苷环化酶C受体。然而，目前尚无肾病综合征(NS)患者血浆和尿液中尿鸟苷水平的相关资料。我们用灵敏的放射免疫法测定了NS患者血浆和尿液中免疫反应性(ir-)尿鸟苷的浓度，并与非肾病肾炎患者进行了比较。NS患者血浆ir-uroguanylin、血压和心胸比率较高，尿ir-urognanylin排泄量较低。NS患者缓解期血浆ir-uroguanylin较入院时显著降低。血浆Ir-尿鸟苷浓度与血清总蛋白、白蛋白浓度呈显著负相关。此外，NS患者的液体滞留与入院至缓解期血浆ir-uroguanylin的变化呈正相关，提示血浆ir-uroguanylin浓度随肾病病情的加重而升高。考虑到其强大的利钠作用，这些发现表明尿鸟苷可能在NS的病理生理机制中发挥作用。

Uroguanylin, a new natriuretic peptide originally isolated from urine, stimulates the membrane guaynlate cyclase C receptor. No information, however, is available on the plasma and urine levels of uroguanlyin in nephrotic syndrome(NS), the state associated with sodium and water retention, using a sensitive redioimmunoassay, we measured the plasma and urine concentrations of immunoreactive (ir-) uroguanylin in NS patients and compared them with those of patients with non-nephrotic glomerulonephritis. Plasma ir-uroguanylin, blood pressure and the cardiothoracic ratio were higher, and urine excretion of ir-urognanylin was lower in the NS patients. Plasma ir-uroguanylin in the NS patients significantly decreased during remission as compared with findings on admission. There was significant inverse correlation between the concentration of plasma ir-uroguanylin and that of serum total protein or albumin. Moreover, fluid retention in the NS patients was correlated with the changes in plasma ir-uroguanylin between admission and remission, indicative that the plasma concentration increases with the severity of the nephrotic state. Taking into account its potent natriuretic effect, these findings suggest that uroguanylin may function in the pathophysiological mechanism in NS.