Parathyroid hormone dynamics in hypoparathyroidism and primary hyperparathyroidism

Abstract

A bstract:Normal pattern of parathyroid response to subsequent induction of calcium lowering and raising has been shown in most patients with surgical hypoparathyroidism and in patients with primary hyperparathyroidism. The relationship of S-PTH to BCa ~ § showed in hypoparathyroid patients with residual PTSH-capacity, an inverse sigmoidal relationship, displaced downwards and to the left, as compared with controls. Whereas, the curve of untreated patients with primary hyperparathyroidism was displaced upwards and to the right, exhibiting significantly raised values for PTH maximum, PTH minimum and Brown's calcium set-point, Furthermore, the slope of the sigmoidal curve in patients with primary hyperparathyroidism was significantly less than in normal humans, which may reflect a reduced sensitivity of parathyroid adenomas to B-Ca 2 § The calcium set-points are raised in primary hyperparathyroidism and return to normal following parathyroidectomy. The values for Brown's and Parfitt's calcium set-points are significantly different, but strikingly well correlated, supporting the view that Brown and Parfitt describe two different points on the same sigmoidal curve, corresponding to 50~ and about 85% inhibition of PTH maximum, respectively.

Recent progress in PTH/PTHrP research

“…Positions and shape of curves are influenced by many factors. Schwarz [18] studied set-point of PTH secretion with regards to calcium levels. Patients with hypoparathyroidism demonstrated the left and downward shift of the sigmoidal curve and those with primary hyperparathyroidism the right and upward shift and the slope of the sigmoidal curve was less.…”

“…The Third International Conference on New Actions of Parathyroid Hormone was held in Kyoto April [18][19][20][21]1994. There has been tremendous progress in the study of PTH/PTHrP since the last Conference in Pisa in 1991.…”