Regulation by calcium and 1,25-(OH)2D3 of cell proliferation and function of bovine parathyroid cells in culture.
The effects of high calcium and 1,25-(OH)2D3 on parathyroid cell growth, PTH secretion, and steady-state levels of pre-proPTH mRNA in proliferating bovine parathyroid cells were examined. Cells were established in primary tissue culture and then tested in passages 2 and 5. Cell proliferation was suppressed by 10(-9)-10(-7) M 1,25-(OH)2D3 but not by high calcium (2.5 mM). Cells at passages 2 and 5 were grown to subconfluence and then exposed for 72 h to 2.5 mM calcium or 10(-7) M 1,25-(OH)2D3. Pre-proPTH mRNA was decreased to approximately 50% of control by 2.5 mM calcium compared with 0.3 and 1.0 mM calcium. PTH secretion, as tested by low calcium stimulation for 1 h at the end of 72 h incubation, was inhibited by 50% in cells that had been exposed to high calcium compared with control. Incubation with 10(-7) M 1,25-(OH)2D3 caused a decrease in the levels of pre-proPTH mRNA and PTH release to 50% of control at 72 h. These results suggest that cultured bovine parathyroid cells, at least in early passages, have responses to high calcium and 1,25-(OH)2D3 similar to those in primary nonproliferating cultures studied earlier and that 1,25-(OH)2D3 inhibits the proliferation of parathyroid cells in a dose-responsive fashion.
Department of Medicine, Albert Einstein College of Medicine, New York, NY 10461.
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Y
Ishimi
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Russell
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LM
Sherwood
D000818:Animals; D002117:Calcitriol / Q000502:physiology*; D002118:Calcium / Q000502:physiology*; D002417:Cattle; D002455:Cell Division / Q000502:physiology; D002478:Cells, Cultured; D010280:Parathyroid Glands / Q000166:cytology* / Q000502:physiology; D010281:Parathyroid Hormone / Q000235:genetics / Q000378:metabolism; D011498:Protein Precursors / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism
D010281:Parathyroid Hormone; D011498:Protein Precursors; D012333:RNA, Messenger; C019056:preproparathormone; D002117:Calcitriol; D002118:Calcium