Biomaterial Database

Vasopressin resistance in potassium depletion: role of Na-K pump. 1992

S K Mujais, and Y Chen, and N A Nora

Department of Medicine, Northwestern University Medical School, Chicago, Illinois.

Resistance to the hydrosmotic effects of vasopressin has been described in K depletion. It is not clear whether other effects of vasopressin, notably its effects on the Na-K pump in the collecting duct, are similarly affected. Adrenalectomized male Sprague-Dawley rats were allocated to either a normal K (NK) or low-K (LK) diet. Na-K pump activity (pmol.mm-1.h-1) in cortical collecting duct (CCD) and medullary collecting duct (MCD) was determined at 21 days after allocation to the dietary groups before and after exogenous vasopressin (0.1 U twice daily for 3 days). In animals on NK diet, vasopressin (AVP) led to a doubling of Na-K pump activity in the CCD from 502 +/- 47 to 1,144 +/- 41 pmol.mm-1.h-1 (P < 0.01). In K-depleted animals, which had a higher baseline Na-K pump activity, an increase was also observed from 1,056 +/- 97 to 1,239 +/- 65 pmol.mm-1.h-1 (P < 0.05), but this increase was quantitatively less, with the change being 183 vs. 642 pmol.mm-1.h-1 in K-replete rats. The findings in the MCD were similar; in rats on a NK diet, AVP led to a significant increase in Na-K pump activity from 498 +/- 29 to 830 +/- 28 pmol.mm-1.h-1 (P < 0.01). With K depletion, this directional change was preserved, increasing from 1,380 +/- 49 to 1,556 +/- 45 pmol.mm-1.h-1 (P < 0.05), but was quantitatively less than in K-replete rats, the change being 176 vs. 332 pmol.mm-1.h-1.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D007672	Kidney Cortex	The outer zone of the KIDNEY, beneath the capsule, consisting of KIDNEY GLOMERULUS; KIDNEY TUBULES, DISTAL; and KIDNEY TUBULES, PROXIMAL.	Cortex, Kidney
D007679	Kidney Medulla	The internal portion of the kidney, consisting of striated conical masses, the renal pyramids, whose bases are adjacent to the cortex and whose apices form prominent papillae projecting into the lumen of the minor calyces.	Kidney Papilla,Kidney Medullas,Kidney Papillas,Medulla, Kidney,Medullas, Kidney,Papilla, Kidney,Papillas, Kidney
D007685	Kidney Tubules, Collecting	Straight tubes commencing in the radiate part of the kidney cortex where they receive the curved ends of the distal convoluted tubules. In the medulla the collecting tubules of each pyramid converge to join a central tube (duct of Bellini) which opens on the summit of the papilla.	Kidney Collecting Ducts,Kidney Collecting Duct,Collecting Duct, Kidney,Collecting Ducts, Kidney
D008297	Male		Males
D011191	Potassium Deficiency	A condition due to decreased dietary intake of potassium, as in starvation or failure to administer in intravenous solutions, or to gastrointestinal loss in diarrhea, chronic laxative abuse, vomiting, gastric suction, or bowel diversion. Severe potassium deficiency may produce muscular weakness and lead to paralysis and respiratory failure. Muscular malfunction may result in hypoventilation, paralytic ileus, hypotension, muscle twitches, tetany, and rhabomyolysis. Nephropathy from potassium deficit impairs the concentrating mechanism, producing POLYURIA and decreased maximal urinary concentrating ability with secondary POLYDIPSIA. (Merck Manual, 16th ed)	Deficiencies, Potassium,Deficiency, Potassium,Potassium Deficiencies
D004351	Drug Resistance	Diminished or failed response of an organism, disease or tissue to the intended effectiveness of a chemical or drug. It should be differentiated from DRUG TOLERANCE which is the progressive diminution of the susceptibility of a human or animal to the effects of a drug, as a result of continued administration.	Resistance, Drug
D000251	Adenosine Triphosphatases	A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.	ATPases,Adenosinetriphosphatase,ATPase,ATPase, DNA-Dependent,Adenosine Triphosphatase,DNA-Dependent ATPase,DNA-Dependent Adenosinetriphosphatases,ATPase, DNA Dependent,Adenosinetriphosphatases, DNA-Dependent,DNA Dependent ATPase,DNA Dependent Adenosinetriphosphatases,Triphosphatase, Adenosine
D000254	Sodium-Potassium-Exchanging ATPase	An enzyme that catalyzes the active transport system of sodium and potassium ions across the cell wall. Sodium and potassium ions are closely coupled with membrane ATPase which undergoes phosphorylation and dephosphorylation, thereby providing energy for transport of these ions against concentration gradients.	ATPase, Sodium, Potassium,Adenosinetriphosphatase, Sodium, Potassium,Na(+)-K(+)-Exchanging ATPase,Na(+)-K(+)-Transporting ATPase,Potassium Pump,Sodium Pump,Sodium, Potassium ATPase,Sodium, Potassium Adenosinetriphosphatase,Sodium-Potassium Pump,Adenosine Triphosphatase, Sodium, Potassium,Na(+) K(+)-Transporting ATPase,Sodium, Potassium Adenosine Triphosphatase,ATPase Sodium, Potassium,ATPase, Sodium-Potassium-Exchanging,Adenosinetriphosphatase Sodium, Potassium,Pump, Potassium,Pump, Sodium,Pump, Sodium-Potassium,Sodium Potassium Exchanging ATPase,Sodium Potassium Pump
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001127	Arginine Vasopressin	The predominant form of mammalian antidiuretic hormone. It is a nonapeptide containing an ARGININE at residue 8 and two disulfide-linked cysteines at residues of 1 and 6. Arg-vasopressin is used to treat DIABETES INSIPIDUS or to improve vasomotor tone and BLOOD PRESSURE.	Argipressin,Vasopressin, Arginine,Arg-Vasopressin,Argipressin Tannate,Arg Vasopressin