Micropuncture study of renal transtubular concentration gradients of sodium and potassium in adrenalectomized rats

Hierholzer, Klaus; Wiederholt, Michael; Holzgreve, H; Giebisch, Gerhard; Klose, Ruth M.; Windhager, Erich E.

doi:10.1007/bf00362623

Cited by 118 publications

(40 citation statements)

References 30 publications

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“…In free flow experiments (Table 2), however, the TF/P Na concentration ratio fell from 0.48-10.05 to 0.33±0.05 after the administration of aldosterone. This result agrees with data obtained by Hierholzer et al (7). The mean TF/P osmolality ratio also fell from 0.75+0.06 to 0.68+0.10, but this was not significant.…”

Section: Effect Of Aldosteronesupporting

confidence: 92%

Effects of Aldosterone and Cortisol on Henle's Loop in the Adrenalectomized Rat's Kidney

Sakai

Murayama

1971

Jpn.J.Pharmacol

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It is generally accepted that urine is concentrated by the mammalian kidney through the operation of a countercurrent mechanism in the renal medulla and that active sodium transport out of the ascending limb of Henle's loop plays an important role in this mecha nism. In addition, it has been reported that in the adrenalectomized rat urine volume is decreased and the corticomedullary osmotic gradient lowered (1, 2).Experiments studying the effects of aldosterone on free water clearance (3) and the attainment of maximum urinary osmolality (4), have suggested that aldosterone may cause an increased rate of transport of sodium from the inside of the ascending limb of Henle's loop to the surrounding tissue. On the other hand, the action of glucocorticoids, particu larly their effects on the loop of Henle have not yet been precisely defined. Experiments dealing with free water reabsorption (T°H2O) indicated, that glucocorticoids may enhance sodium transport at the ascending limb (5, 6). Hierholzer's experiments (7) suggested that cortisol affects the water permeability of distal tubular segments. In the present experiments we have attempted, by microperfusion of Henle's loop in the kidneys of ad renalectomized rats, to clarify the mode of action of corticosteroids on these tubular seg ments. METHODSMale albino rats weighing 150-230g were adrenalectomized and given free access to 0.9% saline and a dry pellet diet. Intact rats were kept on tap water. The following groups of rats were studied (a) intact animals on controls, (b) adrenalectomized animals 18-24 hours, 4 days and 7-9 days after operation, (c) animals adrenalectomized 7-9 days previously and given 12.5 micrograms of d-aldosterone monoacetate (Aldocorten, Ciba) subcutaneously prior to anesthesia. A further dose of 3.1 micrograms was given intra venously when the kidney had been prepared for micropuncture, (d) animals adrenalecto mized 7-9 days previously and given a subcutaneous injection of 2.5 mg cortisol (alcohol free, Merck) for 2 days. In some animals of this group, 5 mg of cortisol was given daily for 3 days prior to micropuncture. (e) The final group of animals were given both a] dosterone and cortisol similarly to those of group c and d.

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Section: Effect Of Aldosteronesupporting

confidence: 92%

Effects of Aldosterone and Cortisol on Henle's Loop in the Adrenalectomized Rat's Kidney

Sakai

Murayama

1971

Jpn.J.Pharmacol

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“…Previous direct information relating to the discrete functional characteristics of the distal convoluted tubule (DCT)1 has been derived from micropuncture studies (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19). In addition, indirect information concerning the characteristics of the DCT has been obtained from clearance (20)(21)(22)(23)(24)(25)(26) and from toad bladder experiments (27)(28)(29)(30).…”

Section: Introductionmentioning

confidence: 99%

A functional comparison of the cortical collecting tubule and the distal convoluted tubule.

Gross¹,

Imai²,

Kokko³

1975

J. Clin. Invest.

167

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AB STRA CT Electrical and permeability features of the distal convoluted tubule (DCT) and the cortical collecting tubule (CCT) were examined using the technique in which isolated segments of rabbit tubules were perfused in vitro. When rabbits were given a regular diet and tubules were perfused and bathed in artificial solutions simulating plasma ultrafiltrate, the potential difference (PD) was + 3.7+1.9 mV in the CCT and -40.4±2.8 mV in the DCT. When rabbits were given a low sodium, high potassium diet plus i.m. deoxycorticosterone acetate (DOCA) (1 mg/kg per day), the PD in both the CCT (-30.8±3.9 mV) and the DCT (-33.8±5.5 mV) was negative. The PD in the CCT was quantitatively similar to that of diet plus DOCA when animals were given DOCA alone. The PD in both segments was inhibited by ouabain (10' M) in the bath or by amiloride (10' M) in the perfusate. Addition of vasopressin (200 AU/ml) to the bath caused a gradual decline of PD to zero in the CCT but failed to produce a potential response in the DCT. Osmotic water permeability was essentially zero in both segments in the absence of vasopressin. After addition of the vasopressin to the bath, osmotic water permeability in the DCT remained zero but increased to 71.9+25.5 x 10-7 cm/s per atm in the CCT. We conclude that both segments are similar in that each possesses an electrogenic transport process but that these segments differ in that: (a) the CCT requires either exogenous or endogenous mineralocorticoid to maintain a maximal negative PD, whereas the PD in the DCT appears to be independent of mineralocorticoid effect; and (b) the CCT responds to vasopressin with a marked rise in water permeability, whereas the DCT is impermeable to water before and after addition of vasopressin.Dr. Imai's present address is the Department of Pharmacology, Jichi Medical School, Tochigi, Japan 329-04.

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“…There is still considerable confusion as to whether aldosterone promotes sodium reabsorption in the proximal convolution and in the thick ascending limb of Henle. One group of investigators reported a correction of impaired sodium reabsorption at both tubular sites by aldosterone (15,23). This could not be confirmed by others (24,25).…”

Section: Methodsmentioning

confidence: 92%

“…In our study the aldosterone effect on Na-K-ATPase activity could be detected in the proximal and distal tubules (Table III). Micropuncture studies confirm that the sites of aldosterone action are the distal convolution and the collecting duct (23). There is still considerable confusion as to whether aldosterone promotes sodium reabsorption in the proximal convolution and in the thick ascending limb of Henle.…”

Section: Methodsmentioning

confidence: 99%

Sodium- and potassium-activated ATPase. A possible target of aldosterone.

Schmidt¹,

Schmid²,

Schmid³

et al. 1975

J. Clin. Invest.

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Micropuncture study of renal transtubular concentration gradients of sodium and potassium in adrenalectomized rats

Cited by 118 publications

References 30 publications

Effects of Aldosterone and Cortisol on Henle's Loop in the Adrenalectomized Rat's Kidney

Effects of Aldosterone and Cortisol on Henle's Loop in the Adrenalectomized Rat's Kidney

A functional comparison of the cortical collecting tubule and the distal convoluted tubule.

Sodium- and potassium-activated ATPase. A possible target of aldosterone.

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