Effects of parathyroid hormone on cyclic AMP-formation and cytoplasmic free Ca2+ in the osteosarcoma cell line UMR 106-01.
The effects of parathyroid hormone (PTH) on cytoplasmic free Ca2+ (Cai2+) and cAMP-formation were investigated in the rat osteosarcoma cell line UMR 106-01. In fura-2 loaded adherent single cells bPTH 1-34 (10 nM - 1 microM) induced a rapid transient increase in Cai2+ in 11% of the studied cells. In fura-2 tracings from UMR 106-01 cells in suspension, bPTH 1-34 (0.1 microM) induced a transient increase in Cai2+ in 20% of the experiments. The transient increase in Cai2+ seen in suspensions of cells was not abolished by addition of EGTA (2.5 mM) prior to challenge with PTH, suggesting that the increase in Cai2+ was derived from intracellular stores. A marked rapid increase in cAMP-formation was observed in all experiments with cells in suspension, also in the experiments where PTH did not affect Cai2+. These data show that PTH causes a release of Ca2+ from intracellular stores in a small percentage of osteosarcoma UMR 106-01 cells, and that PTH is capable of inducing an increase in cAMP-formation without affecting Cai2+ in osteoblasts.
Ljunggren
O
O
Department of Internal Medicine, University Hospital, Uppsala, Sweden.
Johansson
H
H
Lerner
U H
UH
Lindh
E
E
Ljunghall
S
S
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D000242:Cyclic AMP / Q000096:biosynthesis*; D003593:Cytoplasm / Q000378:metabolism; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism; D012516:Osteosarcoma / Q000378:metabolism; D010281:Parathyroid Hormone / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D019379:Teriparatide; D014407:Tumor Cells, Cultured / Q000378:metabolism
D010281:Parathyroid Hormone; D010446:Peptide Fragments; D019379:Teriparatide; D000242:Cyclic AMP; D002118:Calcium