Intraoperative Secretion of Intact Parathyroid Hormone and Amino-Terminal Parathyroid Hormone Fragments from Normal Parathyroid Glands Associated with Solitary Parathyroid Adenoma

p < 0.05 for both). Because the reduction was more pronounced for i-PTH than for N-PTH, the N/i ratio increased from 0.54 ± 0.33 to 3.76 ± 1.62 ( p < 0.05). Furthermore, the levels of i-PTH and N-PTH were higher centrally than peripherally both before and after adenoma excision ( p < 0.05). The results therefore suggest that the secretion of i-PTH and N-PTH in the remaining normal-size parathyroid glands is not completely suppressed. Furthermore, in these parathyroid glands the secretion of amino-terminal PTH fragments is relatively predominant when compared to the release of the intact PTH. The findings underscore the importance of the N-terminal PTH fragment for maintaining calcium homeostasis during the early postoperative period after surgery for pHPT and may explain the rarity of prolonged hypocalcemia after parathyroidectomy.