Sabio J M, García-Estañ J, García del Río C, Vargas F
Departamento de Bioquímica, Facultad de Medicina, Granada, Spain.
Horm Metab Res. 1994 Sep;26(9):409-12. doi: 10.1055/s-2007-1001719.
We assessed the effects of the inhibition of endogenous nitric oxide (NO) synthesis with Nw-nitro-L-arginine methyl ester (L-NAME) on water and sodium handling after NaCl load containing the inhibitor at 0, 0.5, 5 and 50 mg/kg in conscious control, hyper- and hypothyroid rats. L-NAME at 0.5 mg/kg caused a similar decrease in diuresis and natriuresis in control and hypothyroid rats, whereas no changes were seen in the hyperthyroid group. The saline load with 5 mg/kg of L-NAME produced no significant changes with respect to the 0 dose in any variable in control and hypothyroid rats, but increased natriuresis in the hyperthyroid group. The highest dose of L-NAME (50 mg/kg) increased the diuretic and natriuretic response in control and hyperthyroid groups, whereas in the hypothyroid group no urinary variable was significantly modified with respect to the 0 dose. These results indicate that the antidiuretic and antinatriuretic effects of L-NAME at low doses are suppressed in hyperthyroid rats, whereas the diuretic and natriuretic effects at high doses are absent in hypothyroid rats. Our findings suggest that the modulatory role of NO on sodium and water excretion is affected in both thyroid disorders. In addition, the highest dose of L-NAME killed hyperthyroid rats, indicating that NO plays an essential role for life in hyperthyroidism.
我们评估了在清醒的对照、甲状腺功能亢进和甲状腺功能减退大鼠中，用Nω-硝基-L-精氨酸甲酯（L-NAME）抑制内源性一氧化氮（NO）合成对给予含0、0.5、5和50 mg/kg该抑制剂的氯化钠负荷后水和钠处理的影响。0.5 mg/kg的L-NAME使对照和甲状腺功能减退大鼠的利尿和利钠作用出现类似程度的降低，而甲状腺功能亢进组未见变化。含5 mg/kg L-NAME的盐水负荷在对照和甲状腺功能减退大鼠中，任何变量相对于0剂量均未产生显著变化，但在甲状腺功能亢进组中增加了利钠作用。最高剂量的L-NAME（50 mg/kg）增加了对照和甲状腺功能亢进组的利尿和利钠反应，而在甲状腺功能减退组中，相对于0剂量，没有尿液变量发生显著改变。这些结果表明，低剂量L-NAME的抗利尿和抗利钠作用在甲状腺功能亢进大鼠中受到抑制，而高剂量的利尿和利钠作用在甲状腺功能减退大鼠中不存在。我们的研究结果表明，在两种甲状腺疾病中，NO对钠和水排泄的调节作用均受到影响。此外，最高剂量的L-NAME导致甲状腺功能亢进大鼠死亡，表明NO在甲状腺功能亢进症中对生命起着至关重要的作用。
