Method for Non‐destructive Determination of the Sodium Transport Pool in Frog Skin with Radiosodium

Andersen, Birgit; Zerahn, K.

doi:10.1111/j.1748-1716.1963.tb02747.x

Cited by 49 publications

(30 citation statements)

References 11 publications

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“…Accepting thus as a working hypothesis an intracellular location for this pool, it becomes important to evaluate the extent to which it undergoes dilution by sodium entering the cells from the serosal side. In the case of the frog skin, Andersen & Zerahn (1963) produced arguments according to which contamination of this pool is negligible. With the toad bladder, Frazier et al (1962) prevented possible dilution of the pool by replacing sodium with 566 HORMONES AND SODIUM TRANSPORT choline on the serosal surface of the toad bladder.…”

Section: Discussionmentioning

confidence: 99%

Action of aldosterone and vasopressin on the active transport of sodium by the isolated toad bladder.

Crabbé¹,

Weer²

1965

The Journal of Physiology

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Section: Discussionmentioning

confidence: 99%

Action of aldosterone and vasopressin on the active transport of sodium by the isolated toad bladder.

Crabbé¹,

Weer²

1965

The Journal of Physiology

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“…Sizes of the pool of tissue Na with which the isotope equilibrates were calculated from plots of the accumulated appearance of Na on the trans side during the loading or unloading phase (see Andersen & Zerahn, 1963;Cuthbert, 1971). Zero time was taken as the moment when tracer Na could first be detected in the effluent on the trans side (loading pool) or was found to decrease (unloading pool).…”

Section: Generalmentioning

confidence: 99%

Sodium Movements Across the Vascularly Perfused Anuran Small Intestine and Colon

Parsons

1982

Exp Physiol

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SUMMARYValues of unidirectional Na fluxes measured across the vascularly perfused small intestine of three anuran species are higher than those found in other preparations in vitro. In Rana ridibunda and R. pipiens no net movement of Na across the small intestine can be detected. In contrast, the unidirectional fluxes of Na across the colon of R. ridibunda and R. pipiens are lower than across the small intestine and a significant net absorption is found. Apparent loading and unloading pools for Na within the small intestine, as measured with tracer Na under standard experimental conditions, consist largely ofextracellular Na presumably within the bulk phase of the lumen. The size of these pools can be greatly reduced by the rapid addition to or removal from the lumen of tracer. The loading pool appears to occupy not more than about 9% of the total tissue water, equivalent to about 20% of the extracellular water of the tissue. The washout of tracer Na from preloaded small intestine into the vascular bed is bi-exponential and appears from a pool, or pools, of apparent greater size than that of the loading pool. The results show that Na can move very rapidly across the small intestine and suggest that a high proportion of this movement occurs possibly via paracellular shunt pathways.

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“…The size of the 'loading pool', the quantity of substrate required to be present in the tissue in order to achieve a constant rate of transfer into the vascular effluent, was calculated using the measured delay in the time taken to reach the steady state following the addition of substrate to the lumen (Andersen & Zerahn, 1963). The 'unloading pool' size was derived from the quantity of substrate that appears in the vascular effluent following the removal of substrate from the lumen.…”

Section: Methodsmentioning

confidence: 99%

Effects of vascular perfusion on the accumulation, distribution and transfer of 3‐O‐methyl‐D‐glucose within and across the small intestine

Boyd

Parsons

1978

The Journal of Physiology

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SUMM8JY1. Factors affecting the transfer of the non-metabolized, 'actively transported' sugar, 3-0-methyl-D-glucose (3MG) across the small intestinal epithelium have been examined in vascularly perfused anuran intestine. Transfer has been studied during absorption in the steady state, and also during the period of transition from one steady state to another.2. During the steady state, the rate of absorption of 3MG from the intestinal lumen is equal to the rate of appearance in the portal venous effluent; this rate of transfer is to & small, but significant, extent directly related to the rate of arterial perfusion. With phlorizin in the intestinal lumen, transfer across the epithelium is reduced to very low rates which are independent of the rate of vascular perfusion.3. The apparent size of the tissue pool(s) of 3MG that have to be loaded to achieve the steady state rate of transfer are less than those that unload into the vascular bed after 3MG is removed from the intestinal lumen. This 'up-down asymmetry' is abolished when phlorizin is present in the intestinal lumen during the unloading phase.4. When 3MG is abruptly removed from the intestinal lumen after the tissue has been previously loaded with the sugar, the rate of washout into the vascular bed can be described by the sum of two exponential terms. The two terms differ in that the rate constant of the earlier 'fast' term is sensitive to the rate of vascular perfusion, while the later, 'slow', rate constant is insensitive to flow rate. The total quantity of 3MG that can be unloaded from the tissue into the portal venous effluent is decreased when phlorizin is present in the intestinal lumen during the unloading phase.5. Absorption from the lumen of the anuran intestine continues while the mesenteric circulation is interrupted. An estimate of the concentration of 3MG during the period of vascular stoppage can be made from the quantity recovered in the portal venous effluent when vascular perfusion is reinstituted ('vascular stop-flow'). The extent of the accumulation depends upon the duration of the vascular stoppage and the presence of Na ions in the intestinal lumen is essential for accumulation to occur.6. The findings are discussed in relation to the transfer of 3MG between various * Present address: Department of Physiology, University of Dundee, Dundee DD1 4HN.C. A. R. BOYD AND D. S. PARSONS possible compartments in the tissue during absorption. Evidence is presented that a re-uptake of previously absorbed 3MG may occur across the brush border membrane. Such a recycling of 3MG across the epithelium implies that the apparent unidirectional fluxes measured across the epithelium between the bulk phase of the lumen and the blood may underestimate the size of fluxes across the epithelium at the cellular level.

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Method for Non‐destructive Determination of the Sodium Transport Pool in Frog Skin with Radiosodium

Abstract: ANDERSEN, B. and K. ZERAHN. Method f o r non-destructive determination of the sodium transport pool in frog skin with radiosodium. Acta physiol. scand. 1963. 59. [319][320][321][322][323][324][325][326][327][328][329]. -A method is described for measuring

Cited by 49 publications

References 11 publications

Action of aldosterone and vasopressin on the active transport of sodium by the isolated toad bladder.

Action of aldosterone and vasopressin on the active transport of sodium by the isolated toad bladder.

Sodium Movements Across the Vascularly Perfused Anuran Small Intestine and Colon

Effects of vascular perfusion on the accumulation, distribution and transfer of 3‐O‐methyl‐D‐glucose within and across the small intestine

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