Effect of triethyltin on Ca2+ movement in Madin-Darby canine kidney cells.
The effects of the environmental toxicant, triethyltin, on Ca2+ mobilization in Madin-Darby canine kidney (MDCK) cells have been examined. Triethyltin induced an increase in cytosolic free Ca2+ levels ([Ca2+]i) at concentrations larger than 2 microM in a concentration-dependent manner. Within 5 min, the [Ca2+]i signal was composed of a gradual rise and a sustained phase. The [Ca2+]i signal was partly reduced by removing extracellular Ca2+. In Ca(2+)-free medium, pretreatment with thapsigargin (1 microM), an endoplasmic reticulum Ca2+ pump inhibitor, reduced 50 microM triethyltin-induced [Ca2+]i increase by 80%. Conversely, pretreatment with triethyltin abolished thapsigargin-induced Ca2+ release. Pretreatment with U73122 (2 microM) to inhibit phospholipase C-coupled inositol 1,4,5-trisphosphate formations failed to alter 50 microM triethyltin-induced Ca2+ release. Incubation with triethyltin at a concentration (1 microM) that did not increase basal [Ca2+]i for 3 min did not alter ATP (10 microM)- and bradykinin (1 microM)-induced [Ca2+]i increases. Collectively, this study shows that triethyltin altered Ca2+ movement in renal tubular cells by releasing Ca2+ from multiple stores in an inositol 1,4,5-trisphosphate-independent manner, and by inducing Ca2+ influx.
Jiann
B P
BP
Department of Surgery, Kaohsiung Veterans General Hospital, Taiwan, ROC.
Chou
K J
KJ
Chang
H T
HT
Chen
W C
WC
Huang
J K
JK
Jan
C R
CR
D000818:Animals; D002118:Calcium / Q000493:pharmacokinetics*; D018929:Cell Culture Techniques; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004785:Environmental Pollutants / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007668:Kidney / Q000166:cytology / Q000502:physiology*; D015398:Signal Transduction; D019284:Thapsigargin / Q000494:pharmacology; D014267:Triethyltin Compounds / Q000494:pharmacology*
D004785:Environmental Pollutants; D004791:Enzyme Inhibitors; D014267:Triethyltin Compounds; C031575:triethyltin; D019284:Thapsigargin; D002118:Calcium