Immunoheterogeneity of Parathyroid Hormone in Venous Effluent Serum from Hyperfunctioning Parathyroid Glands

A B S T R A C T The immunoreactive parathyroid hor- mone (iPTH) in the plasma of hyperparathyroid man consists largely of carboxyl (COOH)-terminal frag- ments of the hormone. Although these fragments have been thought to arise principally or solely from peripheral metabolism of intact human PTH {hPTH(l- 84)} secreted from the parathyroid gland, there is dis- agreement about the source of iPTH fragments in vivo.