The distribution of sodium-potassium-activated adenosine triphosphatase in medulla and cortex of the kidney

Hendler, Ernesto D.; Torretti, Jorge; Epstein, Franklin H.

doi:10.1172/jci106612

Cited by 62 publications

(25 citation statements)

References 33 publications

(34 reference statements)

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“…The Na+K+ATPase system of kidney has been studied extensively (7,14,16,17,50). Because kidney does not have a known stimulus-secretion coupling reaction in response to insulinotropic substances, we have compared islet ATPases with those of kidney.…”

Section: Resultsmentioning

confidence: 99%

“…Dark-red outer renal medulla was obtained by incisions along the boundaries between cortex and light gray inner medulla (14). This region was used because preliminary experiments in our laboratory, and the work of others (14), indicated the highest Na+K+ATPase activity is found here. Approximately 13 mg (wet weight) of outer renal medulla was obtained for subsequent homogenization.…”

Section: Methodsmentioning

confidence: 99%

“…For Ca++ATPase, the kidney was thawed and washed in 0.3 M sucrose and 10 mM Tris HCl. On a cold Petri dish, approximately 13 mg (wet weight) of inner cortex (14,15) was dissected out with a scalpel and forceps, and saved in 2 ml of sucrose-Tris solution for subsequent homogenization. Inner cortex was used for Ca++ATPase assay because our preliminary experiments and the work of others (15) showed that this renal region is highest in this enzyme activity.…”

Section: Methodsmentioning

confidence: 99%

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Adenosine Triphosphatases of Rat Pancreatic Islets

Levin¹,

Kasson²,

Driessen³

1978

J. Clin. Invest.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Adenosine Triphosphatases of Rat Pancreatic Islets

Levin¹,

Kasson²,

Driessen³

1978

J. Clin. Invest.

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“…Both cortical and medullary renal tissues are rich in Na+,K+-ATPase. It is of importance that the enzyme activity in the medulla is at least two to four times higher than that of cortex (3)(4)(5)(6). The bulk of cortical tissue consists mainly of proximal convolutions, a site where isosmotic sodium reabsorption takes place.…”

Section: Introductionmentioning

confidence: 99%

Renal Sodium-Potassium-Activated Adenosine Triphosphatase and Sodium Reabsorption

Martinez-Maldonado¹,

Allen²,

Inagaki³

et al. 1972

J. Clin. Invest.

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A B S T R A C T The role of renal Na+,K+-ATPase in sodium reabsorption was further examined in dogs in which digoxin, a specific inhibitor of the enzyme system, was infused into one renal artery in doses ranginig from 0.4 to 0.9 /Ag/kg/min (low dose) and from 1.0 to 4.0 Ag/kg/ min (high dose). A significant natriuresis occurred with both dose ranges which was accompanied by inhibition of Na+,K+-ATPase of cortex and nmedulla in the infused kidney. Despite over 90% enzyme inhibition in many experiments, at least 80% of the filtered sodium continued to be reabsorbed. The per cent change in enzyme activity correlated with the rate of digoxin administration and the total dose administered but not with changes in sodium excretion. Changes in medullary Na+,K+-ATPase activity, however, bore a direct relationship to alterations in fractional solute free water reabsorption (TcH1o). Inhibition of cortical enzyme activity alone was not associated with natriuresis, suggesting that medullary enzyme activity must be depressed for increased sodium excretion to occur during digoxin infusion. In high-dose experiments, significant inhibition of cortical and medullary enzyme in the contralateral control kidney was also observed, but natriuresis did not occur. In these experiments the rate at which digoxin reached the control kidney rose progressively but never equaled the rates in the directly infused kidney with either dose. Nevertheless, it is clear that under certain circumstances enzyme inhibition of either cortex or medulla need not be accompanied by natriuresis. We conclude that the major role of renal Na+,K+-ATPase is in sodium reabsorption in the medulla (ascending limb of Henle's loop) and that it has a relatively small role in proximal sodium reabsorption. The Dr. Tsaparas is a Hoechst International Fellow in Nephrology.

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“…Sodium-potassium-activated adenosine triphosphatase (Na-K-ATPase) is known to be present at a high concentration in the kidney (11,18,24), and is thought to play an important role in the reabsorption process of sodium in this organ (8,21,31). The nephron which is the functional unit of the kidney differs in structure and function according to its intrarenal location, namely, superficial or juxtamedullary nephron, and differs even in the same nephron among its parts such as proximal or distal segments (22,28,32,35).…”

mentioning

confidence: 99%