MECHANISM OF OSMOTIC DIURESIS
MECHANISM OF OSMOTIC DIURESIS
复制标题
DOI：
10.1038/ki.1981.36
复制
发表时间：
1981-01-01
影响因子：
19.6
通讯作者：
KIIL, F
中科院分区：
文献类型：
--
作者：
MATHISEN, O;RAEDER, M;KIIL, F
甘露醇可能通过降低渗透驱动力来抑制近端小管对水和氯化钠的细胞旁重吸收。在麻醉犬中检验了这一假设。碳酸氢钠输注可使重吸收保持恒定，依他尼酸可抑制跨细胞氯化钠重吸收。通过改变肾灌注压来改变肾小球滤过率（GFR）。甘露醇输注减少氯化钠重吸收从62-33。过滤负载的5%。计算出的rebibate渗透压摩尔浓度的增加，平均为82 . ±. 6 mOsm/kg H2O，归因于碳酸氢钠，等于血浆渗透压摩尔浓度的增加。甘露醇浓度平均值为81 ± 0.01。血浆中7 mM，101 . ±.尿液中12 mM。在甘露醇输注前后，在相同的GFR范围内，重吸收与GFR（肾小球肾小管平衡）之间保持线性关系。甘露醇输注可使每摩尔重吸收碳酸氢钠的氯化钠重吸收从2.6-1.4摩尔减少。在甘露醇输注过程中，乙酰唑胺抑制碳酸氢钠重吸收的对照实验，但减少氯化钠重吸收less. Apparently，减少水重吸收增加碳酸氢钠浓度的细胞旁液中的甘露醇浓度升高血浆和肾小球滤液。沿着近端小管，随着甘露醇浓度的升高，净渗透力逐渐降低，这是水和氯化钠重吸收减少的原因。
Mannitol might inhibit paracellular reabsorption of water and sodium chloride in the proximal tubules by reducing the osmotic driving force. This hypothesis was examined in anesthetized dogs. Bicarbonate reabsorption was kept constant by sodium bicarbonate infusion and transcellular sodium chloride reabsorption was inhibited by ethacrynic acid. The glomerular filtration rate (GFR) was varied by altering renal perfusion pressure. Mannitol infusion reduced sodium chloride reabsorption from 62-33 .+-. 5% of the filtered load. The calculated increase in reabsorbate osmolality, averaging 82 .+-. 6 mOsm/kg H2O, was due to sodium bicarbonate and equalled the increase in plasma osmolality. Mannitol concentration averaged 81 .+-. 7 mM in plasma and 101 .+-. 12 mM in urine. A linear relationship between reabsorption and GFR (glomerulotubular balance) was maintained over the same range of GFR before and after mannitol infusion. Mannitol infusion reduced sodium chloride reabsorption from 2.6-1.4 mol for each mole of sodium bicarbonate reabsorbed. During mannitol infusion, acetazolamide inhibited sodium bicarbonate reabsorption as in control experiments but reduced sodium chloride reabsorption less. Apparently, reduced water reabsorption increases sodium bicarbonate concentration in the paracellular fluid as much as mannitol concentration is raised in the plasma and glomerular filtrate. Along the proximal tubules, net osmotic force is progressively reduced as mannitol concentration rises, accounting for reduced water and sodium chloride reabsorption.