Thrombin increases cytoplasmic Ca2+ and stimulates formation of prostaglandin E2 in the osteoblastic cell line MC3T3-El.
Using microfluorometric analysis in individual, fura-2 loaded cells, we found that thrombin (0.1-10 U/ml) caused a dose-dependent (EC50 approximately 0.5 U/ml), rapid (within seconds), transient increase in cytoplasmic Ca2+ in the osteoblastic cell line MC3T3-El. The thrombin induced rise in cytoplasmic Ca2+ was not dependent on extracellular Ca2+ and was unaffected by indomethacin. In MC3T3-El cells, thrombin (0.3-10 U/ml) caused a rapid and dose-dependent (EC50 approximately 0.5 U/ml) stimulation of PGE2 formation. The calcium ionophore A23187 (2 mumol/l) also rapidly stimulated an increase in cytoplasmic Ca2+ and the formation of PGE2 in MC3T3-El cells. These data indicate that thrombin mobilizes Ca2+ from intracellular stores and that Ca2+ may serve as a second messenger in thrombin induced stimulation of PGE2 biosynthesis in osteoblasts.
Ljunggren
O
O
Department of Oral Pathology, University of Umeå, Sweden.
Johansson
H
H
Ljunghall
S
S
Lerner
U H
UH
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D003593:Cytoplasm / Q000378:metabolism; D015232:Dinoprostone / Q000096:biosynthesis* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D016257:Fura-2 / Q000378:metabolism; D007213:Indomethacin / Q000494:pharmacology; D051379:Mice; D008856:Microscopy, Fluorescence; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism*; D011863:Radioimmunoassay; D015290:Second Messenger Systems; D013917:Thrombin / Q000494:pharmacology*
D000001:Calcimycin; D013917:Thrombin; D015232:Dinoprostone; D002118:Calcium; D016257:Fura-2; D007213:Indomethacin