Pancreatic polypeptide (PP) immunoreactivity in human parathyroid culture media

Media from cultures of normal and abnormal human parathyroid fragments were assayed for parathyrin (PTH) and pancreatic polypeptide (PP) using sensitive radioimmunoassays. PP immunoreactivity was present in media (Day 6-7 in vitro) from cultures of 3/10 adenomas and 6/6 3 degrees hyperplastic glands (mean = 126. fmole/mg protein/day) (range = 6.-675.), and was not suppressed by 0 leads to 3 mM calcium challenge. PP was undetectable in media from cultures of one parathyroid carcinoma, one 1 degree hyperplasia, and one normal parathyroid. Medium C-terminal PTH levels were quite variable (26.-2,545,000. pg/mg protein/day). Presence of PP immunoreactivity in media from cultures of some hyperplastic parathyroids and some parathyroid adenomas suggests that PP may be released from these tissues in vitro. The significance of elevated PP levels in the MEA syndromes may be of special clinical relevance to this observation.