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Documentation of angiotensin II receptors in glomerular epithelial cells. Am J Physiol 1998 Mar;274(3 Pt 2):F623-7 PMID: 9530280

Abstract

Angiotensin II decreases glomerular filtration rate, renal plasma flow, and glomerular capillary hydraulic conductivity. Although angiotensin II receptors have been demonstrated in mesangial cells and proximal tubule cells, the presence of angiotensin II receptors in glomerular epithelial cells has not previously been shown. Previously, we have reported that angiotensin II caused an accumulation of cAMP and a reorganization of the actin cytoskeleton in cultured glomerular epithelial cells. Current studies were conducted to verify the presence of angiotensin II receptors by immunological and non-peptide receptor ligand binding techniques and to ascertain the activation of intracellular signal transduction in glomerular epithelial cells in response to angiotensin II. Confluent monolayer cultures of glomerular epithelial cells were incubated with angiotensin II, with or without losartan and/or PD-123,319 in the medium. Membrane vesicle preparations were obtained by homogenization of washed cells followed by centrifugation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of membrane proteins followed by multiscreen immunoblotting was used to determine the presence of angiotensin II receptor type 1 (AT1) or type 2 (AT2). Angiotensin II-mediated signal transduction in glomerular epithelial cells was studied by measuring the levels of cAMP, using radioimmunoassay. Results obtained in these experiments showed the presence of both AT1 and AT2 receptor types in glomerular epithelial cells. Angiotensin II was found to cause an accumulation of cAMP in glomerular epithelial cells, which could be prevented only by simultaneous use of losartan and PD-123,319, antagonists for AT1 and AT2, respectively. The presence of both AT1 and AT2 receptors and an increase in cAMP indicate that glomerular epithelial cells respond to angiotensin II in a manner distinct from that of mesangial cells or proximal tubular epithelial cells. Our results suggest that glomerular epithelial cells participate in angiotensin II-mediated control of the glomerular filtration barrier.

Author List

Sharma M, Sharma R, Greene AS, McCarthy ET, Savin VJ

Author

Andrew S. Greene PhD Interim Vice Chair, Chief, Professor in the Biomedical Engineering department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Binding, Competitive
Blotting, Western
Cells, Cultured
Cyclic AMP
Epithelial Cells
Imidazoles
Kidney Glomerulus
Losartan
Pyridines
Rats
Receptor, Angiotensin, Type 1
Receptor, Angiotensin, Type 2
Receptors, Angiotensin
Signal Transduction



View this publication's entry at the Pubmed website PMID: 9530280
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