The calmodulin antagonist W-7 depletes intracellular calcium stores in FRTL-5 thyroid cells.
Incubating Fura 2 loaded thyroid FRTL-5 cells with the calmodulin inhibitor W-7 decreased the ATP-evoked increase in intracellular free calcium. In addition, pretreatment of the cells with W-7 decreased both the thapsigargin-evoked release of sequestered calcium and the entry of extracellular calcium. Studies with 45Ca2+ showed that W-7 decreased the amount of sequestered calcium in the cells. Furthermore, after stimulating with ATP, the ability to sequester calcium was decreased in cells treated with W-7 compared with control cells. The results suggest that calmodulin is necessary for the signal-transduction system in FRTL-5 cells, and may be especially important in maintaining functional intracellular calcium stores in the cells.
Törnquist
K
K
Endocrine Research Laboratory, University of Helsinki, Finland.
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D002147:Calmodulin / Q000037:antagonists & inhibitors*; D002460:Cell Line; D007700:Kinetics; D051381:Rats; D013449:Sulfonamides / Q000494:pharmacology*; D013729:Terpenes / Q000494:pharmacology; D019284:Thapsigargin; D013961:Thyroid Gland / Q000187:drug effects / Q000378:metabolism*
D002147:Calmodulin; D013449:Sulfonamides; D013729:Terpenes; C017967:W 7; D019284:Thapsigargin; D000255:Adenosine Triphosphate; D000252:Calcium-Transporting ATPases; D002118:Calcium