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Query: UNIPROT:P41181 (collecting duct)
 5,183 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cortical collecting duct (CCD) adapts to disturbances of acid/base balance by adjusting the direction and magnitude of its HCO3 transport. The molecular events involved in this adaptation are incompletely understood, but it seems that adaptation is accompanied by changes in the activity and intracellular distribution of the vacuolar H-ATPase. The goal of this study was to examine the effects of metabolic acidosis and alkali load on the expression of the mRNA encoding the 31 kD subunit of the vacuolar H-ATPase in rabbit CCD cells. Pairs of rabbits received either a NH4Cl load or a NaHCO3 load for 16 hours, resulting in a urinary pH of 5.53 +/- 0.38 and 8.42 +/- 0.10, respectively. CCD cells were isolated by immunodissection and mRNA levels of the H-ATPase 31 kD subunit and of beta-actin were determined from the same cDNA samples by quantitative RT-PCR. H-ATPase mRNA levels were significantly higher in CCD cells from acidotic than alkali-loaded rabbits (2.51 +/- 1.3 vs. 0.65 +/- 0.2; P < 0.05). Similar differences in the H-ATPase 31 kD subunit mRNA levels were observed by Northern blotting. beta-actin mRNA levels were comparable in CCD cells of the two groups. The distribution of the H-ATPase 31 kD subunit mRNA was determined among the three cell types of the CCD, that is in alpha- and beta-intercalated cells (alpha-ICC and beta-ICC) and principal cells (PC) isolated by fluorescence-activated cell sorting. The level of expression was comparable in alpha-ICCs and beta-ICCs, whereas PCs contained very low levels of H-ATPase mRNA. In both alpha-ICC and beta-ICC the levels of the 31 kD H-ATPase mRNA were significantly higher in acidotic than in alkali-loaded rabbits. These results indicate that in the rabbit CCD changes in acid/base balance not only regulate the subcellular distribution of the vacuolar H-ATPase but also alter its expression, at least at the mRNA level.
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PMID:Effect of acid/base balance on H-ATPase 31 kD subunit mRNA levels in collecting duct cells. 854 98

The cystic fibrosis transmembrane conductance regulator (CFTR) is a adenosine 3',5'-cyclic monophosphate-activated chloride channel located in the apical membrane of many epithelial cells, and it may play a significant role in the kidney. Recent functional evidence from our laboratory suggests that CFTR may be expressed by the cortical collecting duct (CCD). Therefore, in the present study, the reverse transcription-polymerase chain reaction (RT-PCR) technique was utilized to detect CFTR mRNA in the M-1 mouse CCD cell line and in immunoselected rabbit CCD cells. Primers were constructed to amplify the cDNA sequence encoding the first nucleotide binding domain of CFTR. CFTR PCR products were obtained from both M-1 and rabbit CCD cDNA preparations. The identify of the product amplified from M-1 cell cDNA was confirmed by restriction digestion analysis. The rabbit CCD PCR product was sequenced, and its deduced amino acid sequence was found to be 97% homologous to the corresponding regions of human CFTR. The level of CFTR cDNA detected after 30 cycles of amplification of CCD cDNA was only 49 +/- 8 (n = 9) times lower than the level of beta-actin PCR product obtained from the same sample, suggesting that the levels of CFTR mRNA present in the CCD are physiologically relevant. Northern analysis, using a cRNA probe corresponding to the amplified region on the mRNA from CCD cells, revealed a single hybridizing species with a size of approximately 6.5 kb. Finally, CFTR PCR was performed with cDNA preparations originating from principal cells (PC), beta-intercalated cells (beta-ICC), and alpha-ICC obtained by fluorescence-activated cell sorting of rabbit CCD. CFTR PCR products were obtained from all three cell types, with the most abundant levels found in beta-ICC. beta-ICC expressed 25-fold (n = 4, P < 0.001) and 4.5-fold (n = 7, P < 0.001) higher levels than PC and alpha-ICC, respectively. This distribution pattern suggests that, within the CCD, CFTR plays a role primarily in beta-ICC function.
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PMID:CFTR expression in cortical collecting duct cells. 876 45