| Active proton secretion and potassium absorption in the rabbit outer medullary collecting duct. Functional evidence for proton-potassium-activated adenosine triphosphatase. | |
| | |
MedLine Citation:
|
PMID: 2544629 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
We examined the hypothesis that proton-potassium-activated adenosine triphosphatase (H-K-ATPase) mediates K absorption and acidification in the inner stripe of the outer medullary collecting duct (OMCDi). Rabbits were fed a low-K diet (0.55% K) for 7-14 d because we have demonstrated previously that this low-K diet stimulates K-absorptive flux by the OMCDi. Proton secretion was measured as net total CO2 flux (JTCO2) by microcalorimetry. After basal collections, either vehicle or an inhibitor of gastric H-K-ATPase, omeprazole (0.1 mM), was added to the perfusate during the second period. Addition of vehicle to the perfusate changed neither the transepithelial voltage (VT, in millivolts) nor the JTCO2. In contrast, the addition of omeprazole (0.1 mM) to the perfusate abolished JTCO2 (from 14.5 +/- 5.6 to -0.1 +/- 3.1 pmol.mm-1.min-1) without significantly affecting VT. In additional experiments, in 16 tubules there was significant net K absorption (JK) of 5.0 +/- 1.0 pmol.mm-1.min-1 during the basal period, which exceeded the rate of K absorption that could be attributed to a paracellular voltage-mediated pathway (JKP = 1.0 +/- 0.4 pmol.mm-1.min-1, P less than 0.01). Administration of vehicle did not significantly affect either VT or JK. However, omeprazole abolished JK (from 5.1 +/- 1.0 to 0.1 +/- 2.5 pmol.mm-1.min-1) without affecting VT or JNa. The present results demonstrate that the OMCDi possesses an active, omeprazole-sensitive acidification and K-absorptive mechanism. These findings are consistent with the presence of H-K-ATPase activity in this nephron segment. |
| | |
Authors:
|
C S Wingo |
Related Documents
:
|
2701759 - Effect of feeding raw legumes on intestinal absorption: a short review. 11832109 - Rehabilitative therapy of short bowel syndrome: experimental study and clinical trial. 2337149 - Urea gradient-associated fluid absorption with sigma urea = 1 in rat terminal collectin... 9153299 - Grapefruit juice increases felodipine oral availability in humans by decreasing intesti... 7138989 - Effect of body weight on postnatal development of the proximal small intestine of the r... 1972969 - Dietary modulation of small intestinal glutamine transport in intestinal brush border m... 20580779 - Almond consumption improved glycemic control and lipid profiles in patients with type 2... 2262809 - Tissue distribution and prediction of total body folate of rats. 8267659 - Plasma l-arginine levels in a rabbit model of hypercholesterolaemia. |
Publication Detail:
|
Type: In Vitro; Journal Article; Research Support, U.S. Gov't, Non-P.H.S. |
Journal Detail:
|
Title: The Journal of clinical investigation Volume: 84 ISSN: 0021-9738 ISO Abbreviation: J. Clin. Invest. Publication Date: 1989 Jul |
Date Detail:
|
Created Date: 1989-08-03 Completed Date: 1989-08-03 Revised Date: 2009-11-18 |
Medline Journal Info:
|
Nlm Unique ID: 7802877 Medline TA: J Clin Invest Country: UNITED STATES |
Other Details:
|
Languages: eng Pagination: 361-5 Citation Subset: AIM; IM |
Affiliation:
|
Division of Nephrology and Hypertension, University of Florida, Gainesville. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Absorption Animals Bicarbonates / metabolism Female Kidney Tubules / metabolism* Kidney Tubules, Collecting / metabolism* Omeprazole / pharmacology Potassium / metabolism* Protons* Rabbits Sodium / metabolism Sodium-Potassium-Exchanging ATPase / antagonists & inhibitors* Stomach / enzymology |
| Chemical | |
Reg. No./Substance:
|
0/Bicarbonates; 0/Protons; 73590-58-6/Omeprazole; 7440-09-7/Potassium; 7440-23-5/Sodium; EC 3.6.3.9/Sodium-Potassium-Exchanging ATPase |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Expression of multiple Na+,K+-adenosine triphosphatase isoform genes in human hematopoietic cells. B...
Next Document: CD3-negative lymphoproliferative disease of granular lymphocytes containing Epstein-Barr viral DNA.