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Traebert, M; Völkl, H; Biber, J; Murer, H; Kaissling, B (2000). Luminal and contraluminal action of 1-34 and 3-34 PTH peptides on renal type IIa Na-P(i) cotransporter. American Journal of Physiology: Renal Physiology, 275(5):F792-F798.

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Abstract

Parathyroid hormone (PTH) inhibits proximal tubular reabsorption of P(i) by retrieval of type IIa Na-P(i) cotransporters (NaPi-IIa) from the brush-border membrane (BBM). We analyzed by immunohistochemistry whether PTH analogs, signaling through either protein kinase A (PKA) and C (PKC; 1-34 PTH) or only PKC (3-34 PTH), elicit in rat kidney in vivo or in the perfused murine proximal tubule in vitro a retrieval of NaPi-IIa and whether pharmacological agonists or inhibitors of these kinases are able to either mimic or interfere with these PTH effects. Treatment with either 1-34 or 3-34 PTH downregulated NaPi-IIa in rat kidney. In isolated murine proximal tubules 1-34 PTH was effective when added to either the apical or basolateral perfusate, whereas 3-34 PTH acted only via the luminal perfusate. These effects were mimicked by an activation of PKA with 8-bromoadenosine 3',5'-cyclic monophosphate or PKC with 1, 2-dioctanoylglycerol. The luminal action of both PTH peptides was blocked by inhibition of the PKC pathway (calphostin C), whereas the basolateral effect of 1-34 PTH was completely abolished by inhibiting both pathways (H-89 and calphostin C). These results suggest that 1) NaPi-IIa can be internalized by cAMP-dependent and -independent signaling mechanisms; 2) functional PTH receptors are located in both membrane domains; and 3) apical PTH receptors may preferentially initiate the effect through a PKC-dependent mechanism.

Item Type:Journal Article, refereed
Communities & Collections:04 Faculty of Medicine > Institute of Physiology
07 Faculty of Science > Institute of Physiology
DDC:570 Life sciences; biology
Language:English
Date:1 May 2000
Deposited On:11 Feb 2008 12:22
Last Modified:27 Nov 2013 22:07
Publisher:American Physiological Society
ISSN:0002-9513
Related URLs:http://ajprenal.physiology.org/cgi/content/full/278/5/F792
PubMed ID:10807591
Citations:Web of Science®. Times Cited: 87
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