Effect of age on bone calcium and phosphate metabolism in organ culture

Messer, Harold H.; Yuen, Sandra; Copp, D. Harold

doi:10.1007/bf02008215

Cited by 6 publications

References 4 publications

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Net uptake and release of calcium and phosphate by bonein vitro: Effects of medium calcium and phosphate concentrations

1975

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The effects of varying the initial calcium and phosphate concentrations of the culture media on bone calcium and phosphate release were examined, using whole calvaria from 3-day-old mice in 48-hour cultures. The initial calcium and phosphate concentrations of the culture media were varied in the range 3-10 mg/100 ml; either calcium or phosphate alone was changed while the other ion was held constant, or the concentrations of both were varied while the Ca:P ratio was held constant. For all combinations, 3 treatment groups were used: i) control (no added hormone); ii) 0.5 U/ml PTH; iii) 50 mU/ml CT. The release of calcium and phosphate from the bones was greatest at low initial calcium or phosphate concentrations in the media, and least at high initial concentrations. High concentrations of both ions together abolished hormonal responses and resulted in extensive uptake of calcium and phosphate by the bones. The response to PTH was lost at a high concentration of either ion alone, while a response to CT was observed under all experimental conditions except simultaneously high calcium and phosphate concentrations.

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Net uptake and release of calcium and phosphate by bonein vitro: Effects of medium calcium and phosphate concentrations

1975

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A bioassay for parathyroid hormone and other substances affecting bone metabolism

McPartlin

Powell

1976

IJMS

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A bioassay method for measuring parathyroid hormone (PTH) and other substances that influence bone metabolism is described. Monolayers of bone cells are culturedin vitro, then treated with the test material. Biological activity is determined by measuring the resulting rise in bone-cell adenosine 3',5'-monophosphate (cAMP).Treatment with PTH (1-500 ng/ml) produced a dose-dependent increase in bone-cell cyclic AMP levels. Treatment with prostaglandin E2 also caused an elevation in bone-cell cyclic AMP level, whereas oestradiol inhibited the effect of PTH. High calcium concentration inhibited the stimulatory effect of PTH on bone-cell cyclic AMP; variations in phosphate and magnesium concentrations were without effect. Biological activity was demonstrated in various unextracted normal and hypercalcaemic sera.

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