Michael U F, Kelley J, Vaamonde C A
Am J Physiol. 1979 Jun;236(6):F536-40. doi: 10.1152/ajprenal.1979.236.6.F536.
We previously demonstrated a decrease of sodium reabsorption in the proximal superficial nephron of the hypothyroid rat. The present clearance studies were designed to examine the renal handling of bicarbonate in hypothyroid rats. Hypothyroidism was induced by the intraperitoneal injection of Na131I and the animals were studied 10 or more wk thereafter under anesthesia and compared to their age-matched litter-mates. As is characteristic of hypothyroid animals, insulin clearance was lower and fractional urine flow and sodium excretion rates were higher than in the control rats. At the peak of the bicarbonate diuresis and at similar blood pH, PCO2, and bicarbonate levels, fractional renal bicarbonate excretion was significantly higher in the hypothyroid animals: 22 +/- 2 vs. 15 +/- 1%, P less than 0.02. This perturbation of bicarbonate reabsorption of the hypothyroid rats was independent of the influence of extracellular fluid volume expansion and appears closely related to the impaired sodium reabsorptive capacity characteristic of experimental hypothyroidism.
我们之前证明，甲状腺功能减退大鼠近端浅表肾单位的钠重吸收减少。目前的清除率研究旨在检测甲状腺功能减退大鼠对碳酸氢盐的肾脏处理情况。通过腹腔注射Na131I诱导甲状腺功能减退，10周或更长时间后，在麻醉状态下对这些动物进行研究，并与年龄匹配的同窝对照动物进行比较。正如甲状腺功能减退动物的特征那样，与对照大鼠相比，胰岛素清除率较低，尿流分数和钠排泄率较高。在碳酸氢盐利尿高峰期以及相似的血液pH、PCO2和碳酸氢盐水平下，甲状腺功能减退动物的肾脏碳酸氢盐排泄分数显著更高：22±2% 对15±1%，P<0.02。甲状腺功能减退大鼠碳酸氢盐重吸收的这种紊乱与细胞外液容量扩张的影响无关，似乎与实验性甲状腺功能减退所特有的钠重吸收能力受损密切相关。
