Increased collecting tubule sodium reabsorption in nephrotic syndrome

Micropuncture studies (in which samples are taken via micropipettes from different nephron segments) of sodium handling in unilateral nephrotic syndrome in the rat. Although less sodium is filtered in the nephrotic kidney, less is reabsorbed so that the quantity of sodium remaining in the tubular lumen at the end of the distal tubule is the same in the two kidneys. Thus, sodium reabsorption must be increased in the collecting tubules to account for the two-thirds reduction in total sodium excretion in the nephrotic kidney when compared to the normal kidney.