title: Active acromegaly enhances spontaneous parathyroid hormone pulsatility.
abstract: In healthy subjects, parathyroid hormone (PTH) is secreted in a dual fashion, with low-amplitude and high-frequency pulses superimposed on tonic secretion. These 2 components of PTH secretion seem to have different effects on target organs. The aim of our study was to evaluate whether growth hormone excess in acromegaly may modify the spontaneous pulsatility of PTH. Five male patients with newly diagnosed active acromegaly and 8 healthy subjects were evaluated by 3-minute blood sampling for 6 hours. Plasma PTH concentrations were evaluated by multiparameter deconvolution analysis. Plasma PTH release profiles were also subjected to an approximate entropy (ApEn) estimate, which provides an ensemble measure of the serial regularity or orderliness of the release process. In acromegalic patients, baseline serum PTH values were not significantly different from those measured in the healthy subjects, as well as tonic PTH secretion rate, number of bursts, fractional pulsatile PTH secretion, and ApEn ratio. Conversely, PTH pulse half-duration was significantly longer in acromegalic patients vs healthy subjects (11.8+/-0.95 vs 6.9+/-1.6 minutes; P=.05), whereas PTH pulse mass showed a tendency (P=.06) to be significantly greater in acromegalic patients. These preliminary data suggest that growth hormone excess may affect PTH secretory dynamics in patients with acromegaly. Potentially negative bone effects of the modifications of PTH secretory pattern in acromegaly should be investigated.
authors.affiliation: Department of Internal Medicine, University of Brescia, 25125 Brescia, Italy.
authors.forename: Gherardo
authors.initials: G
authors.lastname: Mazziotti
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Cimino
authors.forename: Ernesto
authors.initials: E
authors.lastname: De Menis
authors.forename: Stefania
authors.initials: S
authors.lastname: Bonadonna
authors.forename: Giovanna
authors.initials: G
authors.lastname: Bugari
authors.forename: Laura
authors.initials: L
authors.lastname: De Marinis
authors.forename: Johannes D
authors.initials: JD
authors.lastname: Veldhuis
authors.forename: Andrea
authors.initials: A
authors.lastname: Giustina
mesh_terms: D000172:Acromegaly / Q000378:metabolism*; D000328:Adult; D016022:Case-Control Studies; D019277:Entropy; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood / Q000378:metabolism*; D011673:Pulsatile Flow
chemical_list: D010281:Parathyroid Hormone