Mechanisms underlying ketoconazole-induced Ca(2+) mobilization in Madin-Darby canine kidney cells.
The effect of ketoconazole on Ca(2+) signaling in Madin-Darby canine kidney (MDCK) cells was investigated by using fura-2 as a Ca(2+) probe. Ketoconazole evoked increases in cytosolic free Ca(2+) concentration ([Ca(2+)](i)) concentration dependently. The response was decreased by external Ca(2+) removal. In Ca(2+)-free medium, pretreatment with ketoconazole abolished the [Ca(2+)](i) rise induced by thapsigargin, an inhibitor of the endoplasmic reticulum Ca(2+) pump. Addition of 3 mM Ca(2+) induced a significant [Ca(2+)](i) rise after preincubation with 150 microM ketoconazole in Ca(2+)-free medium. Pretreatment with aristolochic acid (40 microM) to inhibit phospholipase A(2) inhibited the 150-microM-ketoconazole-induced internal Ca(2+) release by 37%, but inhibition of phospholipase C with 1-(6-((17beta-3-methoxyestra-1,3, 5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione (U73122) (2 microM) had no effect. Collectively, we found that ketoconazole increases [Ca(2+)](i) in MDCK cells by releasing Ca(2+) from thapsigargin-sensitive pools in a manner independent of the production of inositol-1,4,5-trisphosphate, followed by Ca(2+) influx from the external space.
Jan
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C
Department of Medical Education and Research, Veterans General Hospital-Kaohsiung, Kaohsiung, Taiwan. crjan@isca.vghks.gov.tw
Tseng
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C
D000818:Animals; D000935:Antifungal Agents / Q000494:pharmacology*; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D007654:Ketoconazole / Q000494:pharmacology*; D007668:Kidney / Q000166:cytology; D010741:Phospholipases A / Q000037:antagonists & inhibitors / Q000378:metabolism; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000378:metabolism
D000935:Antifungal Agents; D010741:Phospholipases A; D010738:Type C Phospholipases; D007654:Ketoconazole; D002118:Calcium