A bioassay for parathyroid hormone and other substances affecting bone metabolism.

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.