Glucose transport by short loops of Henle in the rat.

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SUMMARY1. Glomerular filtration rate (g.f.r.), and renal reabsorption and excretion of glucose, sodium and potassium were measured in 7-8 day pregnant rats and agematched (12-13 week old) virgin controls undergoing saline and glucose infusions.2. Pregnancy was associated with an increased g.f.r. and a decreased urine flow rate during both infusions.3. During saline infusion, more glucose was excreted in pregnant animals than in virgins but with no significant difference in fractional reabsorption. During glucose infusion, pregnant animals excreted less glucose than virgins, owing to a decrease in the filtered load but with no significant difference in fractional reabsorption.4. During both saline and glucose infusion, pregnant animals excreted less sodium than virgin controls.5. During saline infusion, pregnant animals excreted more potassium. During glucose infusion, pregnant animals excreted less potassium than control animals.

Section: Glucosementioning

confidence: 99%

Effects of pregnancy on glucose handling by rat kidneys.

Bishop¹,

Green²

1980

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“…Although glucose reabsorption in the 'intermediate segment' (between late proximal tubule and distal tubule) (Wen & Stoll, 1979;Wen, Boynar & Stoll, 1983) and 'short loops of Henle' (Von Baeyer, 1975;Bishop, Green & Thomas, 1981) has been shown previously, determination of the tubular location of glucose transport from micropuncture data is complicated by the possible nephron heterogeneity in glucose transport between the cortical and juxtamedullary nephrons.…”

Section: Discussionmentioning

confidence: 99%

Segmental analysis of renal glucose transport in young female rats.

McSherry¹,

Wen²

1984

SUMMARY1. Free-flow micropuncture studies were performed on twenty-seven young female Sprague-Dawley rats before and after 10 % extracellular volume expansion to evaluate glucose reabsorption at the accessible sites of both surface and papillary nephrons.2. In the distal nephron segments no significant glucose reabsorption was observed for the distal tubule and papillary collecting duct but significant difference in fractional glucose delivery was demonstrated between the bend of the Henle's loop and early distal tubule and between the late distal tubule and the base of the collecting duct.3. Comparison of the fractional glucose delivery within the same nephron group for both superficial and juxtamedullary nephrons indicated that glucose reabsorption occurred at some sites beyond the bend of the Henle's loop.4. Volume expansion inhibited glucose reabsorption in the proximal convoluted tubule, enhanced it in the segment between the late proximal and early distal tubules, but had no effect on glucose transport at further distal sites.5. It is concluded that, in addition to the proximal tubule, the ascending loop of Henle or cortical collecting tubule may play a role in maintaining glucose-free urine under physiological conditions.

“…There is evidence that the loop of Henle (von Baeyer, 1975;Bishop et al 1976; Bishop & Green, 1979b) and the collecting duct (Bishop & Green, 1979a) normally reabsorb glucose; and preliminary evidence suggests that reabsorption in both sites is impaired during pregnancy (Bishop & Green, 1979a, b).…”

Section: Glucosementioning

confidence: 99%

“…This conventional description has recently required modification because it has been shown that (a) TmG varies with changes in G.F.R. and extracellular fluid volume (see reviews by Kurtzman & Pillay, 1973;Morel & de Rouffignac, 1973), (b) glucose can be reabsorbed in sites other than the proximal convoluted tubule (von Baeyer, 1975;Bishop, Green & Thomas, 1976;Bishop & Green, 1979a, b).…”

Section: Glucosementioning

confidence: 99%

Effects of pregnancy on glucose reabsorption by the proximal convoluted tubule in the rat.

Bishop¹,

Green²

1981

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SUMMARY1. Free-flow micropuncture techniques were used to investigate glucose, sodium and water reabsorption along the proximal convoluted tubule in 7-8 day pregnant rats undergoing saline or glucose infusion and in virgin controls.2. Absolute proximal tubular reabsorption of glucose was greater in pregnant animals than virgins during both saline and glucose infusion; and fractional reabsorption of glucose was higher in pregnant than in virgin animals during glucose infusion.3. During glucose loading, less glucose escaped reabsorption in the proximal tubule in pregnant than in virgin animals. It is concluded that the increased excretion of glucose observed in pregnant rats cannot be due to failure of proximal tubular mechanisms.4. During saline infusion pregnant animals had a higher single nephron glomerular filtration rate (s.N.G.F.R.) when compared with virgin animals and a corresponding increase in reabsorption of sodium and water. The small increases in S.N.G.F.R. and sodium reabsorption in pregnant animals (compared with virgin animals) during glucose infusion were not statistically significant.5. Fractional reabsorption of sodium (and water) along the proximal convoluted tubule was not significantly different in the four series. It is concluded that glomerulo-tubular balance operates during pregnancy.