Effect of reduction in filtration rate on renal tubular sodium and water reabsorption

The relationship between glomerular filtration rate and sodium reabsorption by the proximal tubule of the rat nephron

“…In order to evaluate the relationship between the absolute reabsorptive rate and tubule volume (equation 5), we measured the transit time of lissamine green to the site of puncture before and after alterations in GFR. As shown in Table II the mean values for transit time during initial and recollection periods in control rats were very nearly the same and agree with values reported by others (6,9,18,13,20). The shorter transit time in the nondiuretic experimental group undoubtedly reflects the somewhat earlier collection sites in this group.…”

“…In the present study, after acute reductions or elevations in GFR, although fractional reabsorption was not constant, in nearly every A * instance there was a change in the absolute rate A of reabsorption, in the same direction, and usually more than half that required to maintain perfect @@* glomerulotubular balance. These findings are simiSchnermann, Klose, and Giebisch (20). The extent to which reabsorption in the proximal tubule is modified when glomerular filtration rate is l____l____l____l____i__ changed is highly relevant to interpretation of the 1.5 2.0 2.5 3.0 3.5 effect of such changes on sodium excretion.…”

An inhibitory effect of furosemide on sodium reabsorption by the proximal tubule of the rat nephron

“…Thus for an elevation in the (TF/P)I ratio to be detected after a diuretic, the volume of fluid entering the pipette from downstream sites will have to be larger. In recent studies in the rat, it has been observed that fractional reabsorption increases after a reduction in nephron GFR (produced by aortic constriction) (11,18,20), and decreases after an elevation in nephron GFR (release of aortic constriction) (11). If it is assumed that nephron GFR changed in the present study to the extent calculated, the data were examined to determine whether the changes in fractional reabsorption after furosemide could be the consequence of these changes in nephron GFR.…”

Regulation by adrenal corticosteroids of sodium and potassium transport in loop of Henle and distal tubule of rat kidney.

“…Receivedfor publication 15 May 1986 and in revisedform 8 August 1986. after adrenalectomy and hormone administration, of changes in glomerular filtration rate and the delivery of sodium and water to the loop of Henle, factors known to have important influences on sodium reabsorption by the loop (12)(13)(14)(15)(16)(17)(18)(19)(20)(21). For example, since glucocorticoids enhance glomerular filtration rate and increase salt and water delivery to the loop of Henle, it is difficult, by free-flow micropuncture techniques, to separate a direct effect of glucocorticoids from these indirect stimulatory factors.…”