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Author Fukunaga, M. ♦ Ochi, S. ♦ Takama, T. ♦ Yokoyama, K. ♦ Fujiwara, Y. ♦ Kamada, T.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword BASIC BIOLOGICAL SCIENCES ♦ PEPTIDES ♦ BIOCHEMICAL REACTION KINETICS ♦ PROSTAGLANDINS ♦ BIOSYNTHESIS ♦ ANIMAL CELLS ♦ CALCIUM COMPOUNDS ♦ DOSE-RESPONSE RELATIONSHIPS ♦ IODINE 125 ♦ RADIOIMMUNOASSAY ♦ RATS ♦ RECEPTORS ♦ ALKALINE EARTH METAL COMPOUNDS ♦ ANIMALS ♦ BETA DECAY RADIOISOTOPES ♦ BIOASSAY ♦ DAYS LIVING RADIOISOTOPES ♦ DIAGNOSTIC TECHNIQUES ♦ ELECTRON CAPTURE RADIOISOTOPES ♦ IMMUNOASSAY ♦ IMMUNOLOGY ♦ INTERMEDIATE MASS NUCLEI ♦ INTERNAL CONVERSION RADIOISOTOPES ♦ IODINE ISOTOPES ♦ ISOTOPE APPLICATIONS ♦ ISOTOPES ♦ KINETICS ♦ MAMMALS ♦ MEMBRANE PROTEINS ♦ NUCLEI ♦ ODD-EVEN NUCLEI ♦ ORGANIC COMPOUNDS ♦ PROTEINS ♦ RADIOASSAY ♦ RADIOIMMUNODETECTION ♦ RADIOIMMUNOLOGY ♦ RADIOISOTOPES ♦ REACTION KINETICS ♦ RODENTS ♦ SYNTHESIS ♦ TRACER TECHNIQUES ♦ VERTEBRATES ♦ Biochemistry- Tracer Techniques
Abstract To study a possible role of endothelin-1 (ET-1) in the regulation of glomerular function, we examined the presence of receptors for, and the biological action of, ET-1 in cultured rat mesangial (M) cells. The first-subcultured M cells prepared from isolated glomeruli of Sprague-Dawley rats were used. ET-1 binding was assayed by using {sup 125}I-ET-1. Inositol 1,4,5-trisphosphate (IP3) was determined by IP3-specific binding assay. Intracellular calcium (iCa{sup 2}{sup +}) was measured in fura-2 loaded cells. Prostaglandin E2 (PGE2) was measured by radioimmunoassay. In M cells there existed two classes of binding sites specific for ET-1 (Kd was 0.24 and 4.4 nmol/L, Bmax was 130 and 1070 fmol/mg, respectively). ET-1 (10{sup {minus} 7} mol/L) induced a rapid and transient increase in IP3, followed by transient and sustained increases in iCa{sup 2}{sup +}. Nicardipine (10{sup {minus} 6} mol/L) inhibited only the sustained increase in iCa{sup 2}{sup +}. ET-1 (10{sup {minus} 9} mol/L to 10{sup {minus} 7} mol/L) significantly stimulated PGE2 production with the concentration dependency. Nicardipine (10{sup {minus} 6} mol/L) and diltiazem (10{sup {minus} 6} mol/L) did not inhibit the PGE2 production. We conclude that M cells have specific ET-1 receptors linked to phosphoinositide turnover and PGE2 production, and PGE2 production by ET-1 may be through an extra-cellular calcium-independent mechanism. Our results suggest that ET-1 plays an important role in the regulation of glomerular functions by modulating PGE2 production in M cells.
ISSN 08957061
Educational Use Research
Learning Resource Type Article
Publisher Date 1991-02-01
Publisher Place United States
Journal American Journal of Hypertension
Volume Number 4
Part 2 t 1


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