The type 1 angiotensin-II receptor mediates intracellular calcium mobilization in rat luteal cells
The intracellular cytosolic calcium concentration ([Ca]i) was determined in cultured rat luteal cells using the calcium-chelating dye fura-2 and microspectrofluorimetry. Angiotensin-II (Ang-II) induced a dose-dependent transient increase in [Ca]i (ED50, 9.0 +/- 6.5 nm). After the initial peak in [Ca...
Elmentve itt :
| Szerzők: | |
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| Dokumentumtípus: | Cikk |
| Megjelent: |
1993
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| Sorozat: | ENDOCRINOLOGY
133 No. 4 |
| Tárgyszavak: | |
| doi: | 10.1210/en.133.4.1678 |
| mtmt: | 2344411 |
| Online Access: | http://publicatio.bibl.u-szeged.hu/32156 |
| Tartalmi kivonat: | The intracellular cytosolic calcium concentration ([Ca]i) was determined in cultured rat luteal cells using the calcium-chelating dye fura-2 and microspectrofluorimetry. Angiotensin-II (Ang-II) induced a dose-dependent transient increase in [Ca]i (ED50, 9.0 +/- 6.5 nm). After the initial peak in [Ca]i, cytosolic calcium returned to a secondary elevated basal level that was dependent upon the presence of extracellular calcium. Pretreatment of rat luteal cells with Ang-II (100 nm) desensitized a subsequent response to a higher concentration (1 mum), but did not desensitize a prostaglandin F2alpha (PGF2alpha)-induced calcium flux. Although the peak increases in [Ca]i induced by Ang-II (1 muM) and PGF2alpha (10 muM) were not significantly different, the plateau phase stimulated by PGF2alpha was significantly higher (P < 0.05) than that stimulated by Ang-II (1 muM). Pretreatment of luteal cells with the type 2 Ang-II receptor antagonist PD 123319 (10 mum) did not inhibit calcium mobilization; however, Ang-II (1 mum)-induced calcium mobilization was dose dependently blocked by the type 1 Ang-II receptor antagonist (DuP 753). The ID50 for Losartan was 5.2 +/- 1.8 nm. Pretreatment of the luteal cells with the endoplasmic reticulum calcium ATPase inhibitor thapsigargin (1 mum) also blocked Ang-II-induced calcium mobilization. These data demonstrate the presence of the type 1 Ang-II receptor in rat luteal cells, through which Ang-II dose dependently mobilizes calcium from an intracellular source, probably the endoplasmic reticulum. |
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| Terjedelem/Fizikai jellemzők: | 1678-1684 |
| ISSN: | 0013-7227 |