Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P41181 (collecting duct)
 5,183 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To examine the role of tubulointerstitial cell interaction in the regulation of fibroblast growth, fibroblasts from the rabbit renal cortex (CF) and papilla (PF) were cocultured with epithelial cells from the same tissue location. Inner medullary collecting duct epithelial cells (IMCDE) or IMCDE-conditioned medium stimulated DNA synthesis in PF, whereas proximal tubule epithelium (PTE) had no effect on the proliferation of CF. PF and CF showed a similar mitogenic response to exogenous epidermal growth factor and insulin-like growth factor 1 (IGF-I). Transforming growth factor-beta 1 inhibited growth of both cell types, and basic fibroblast growth factor (bFGF) had no effect on proliferation of either cell type. In contrast, platelet-derived growth factor (PDGF) was a potent mitogen for PF but was only weakly mitogenic for CF. Both CF and PF expressed a similar number of a single-affinity class of PDGF receptors (Kd, 2-4 x 10(-10) M). Assay for growth factor activity in conditioned medium from IMCDE and PTE showed that only IMCDE produced detectable PDGF. IMCDE-stimulated proliferation of PF was partially blocked by an antibody to PDGF, whereas antibodies to IGF-I had no neutralizing effect. The data suggest a role for PDGF in the regulation of interstitial fibroblast proliferation by IMCDE in the renal papilla. This paracrine system may be important in the pathogenesis of some forms of interstitial fibrosis of the kidney.
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PMID:Fibroblasts of rabbit kidney in culture. II. Paracrine stimulation of papillary fibroblasts by PDGF. 165 5

We have investigated some of the factors known or suspected to influence ion transport by the rat inner medullary collecting duct and have analyzed their actions on active Na+ absorption and active anion secretion by primary cultures. Cells from the terminal 1-2 mm (tip) of the papilla had a lower basal rate of Na+ absorption (2.0 microA/cm2) than cells from the more proximal portions (6.5 microA/cm2). Aldosterone increased Na+ transport approximately sevenfold in the tip cells and approximately threefold in the proximal cells. The magnitude of anion secretion in response to adenosine 3',5'-cyclic monophosphate (cAMP) agonists was similar in the two regions and was unaffected by aldosterone. The morphology of monolayers from both regions was also similar. In monolayers cultured from the entire inner medulla, hypertonic (100 mosM) urea, NaCl, or sucrose reduced Na+ transport but had no significant effect on anion secretion. Transforming growth factor-beta 1, known to blunt the effect of steroids on Na+ transport, had no effect on anion secretion. Finally, cAMP had no effect on Na+ transport, a result that contrasts with its effect on Na+ transport by other epithelial cells demonstrating steroid-responsive, electrogenic Na+ transport. These results demonstrate some potential differences in the magnitude of Na+ transport by position along the inner medulla. They further demonstrate separate regulation of Na+ and anion transport.
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PMID:Separate regulation of Na+ and anion transport by IMCD: location, aldosterone, hypertonicity, TGF-beta 1, and cAMP. 877 Jan 76