Renal Function, Electrolyte Excretion and Body Fluids in Patients With Chronic Renal Insufficiency Before and After Sodium Deprivation 12

The Functional Adaptation of the Diseased Kidney. I. Glomerular Filtration Rate*

“…Simple calculations dictate that if the average value for GFR per nephron increases by 50%o, the great majority of the extra filtered sodium must be reabsorbed, even though the excretion rate (per nephron) increases by as much as tenfold. Thus in advanced renal disease, it is very unusual for more than 15 to 20% of the total filtered load of sodium to be excreted (16). It is implicit, therefore, that the increase in the filtered load far exceeds the increase in excretion.…”

The Mechanism of Salt Wastage in Chronic Renal Disease*

“…It is well known that patients with chronic renal disease have an impaired ability to conserve sodium (1)(2)(3)(4)(5)(6)(7). In a small number of patients this results in profound salt wasting (8)(9)(10)(11)(12)(13), but more commonly the defect is mild and becomes apparent only during severe sodium deprivation.…”

Functional Impairment in Chronic Renal Disease

“…In addition, he stressed the fact that the rate of decline of urinary sodium excretion following sodium restriction is slower than normal in the uremic patient but follows the same type of exponential curve. N ic k e l et al (24) further showed that the uremic patient achieved maximal sodium conservation primarily through a reduction in glomerular filtration rate. The sodium retention occur ring with congestive heart failure in such patients is also accomplished in part through functional changes in renal hemodynamics [ (23), L e v e r e and W esson (17), K n o w les et al (16), V il l a m il et al (39)] that administration of salt-retaining hor mones such as DOCA to patients with renal disease fails to cause sodium retention, suggesting that the tubules of any residual 'intact' nephrons may not be responding normally.…”