The effect of oxotremorine on in-vitro secretion of parathyroid hormone

The effect of the muscarine-like acting parasympathomimetic drug oxotremorine and its antagonist atropine on PTH release was tested using single cell suspensions obtained from a) primary parathyroid adenomas, and b) secondary hyperplastic parathyroid tissue from patients undergoing chronic hemodialysis. For both cell-types we found a dose-dependent suppression of PTH release with oxotremorine. The suppressive activity could be antagonized with atropine, suggesting that parasympathomimetic nerval impulses play a suppressive role in the regulation of PTH release. Muscarine-receptors appear to be responsible for this mechanism.