Chronic glucocorticoid treatment alters spontaneous pulsatile parathyroid hormone secretory dynamics in human subjects

Abstract

Objective: Spontaneous parathyroid hormone (PTH) secretory dynamics include tonic and pulsatile components. It is not known how glucocorticoids might alter these secretory dynamics. Design: The aim of our study was to evaluate spontaneous fluctuations in serum PTH levels in six adult male patients (aged 31-64 years) receiving chronic ( . 6 months) therapy with glucocorticoids (daily dosage . 7.5 mg of prednisone or dose equivalent of other corticosteroid) as compared with a control group of 10 age-and sex-matched normal subjects. Methods: Peripheral venous blood sampling was performed every 3 min for 6 h from 0900 to 1500 h. Plasma PTH release profiles were subjected to deconvolution analysis, a method that resolves measured hormone concentrations into secretion and clearance components, and to an approximate entropy (ApEn) estimate, that in turn provides an integrated measure of the serial regularity or orderliness of the release process. Results: In the glucocorticoid-treated group, the PTH tonic secretory rate was reduced (4.3^0.74 vs 8.8^1.4 pg/ml per min in controls, P ¼ 0.017). There was, however, an increase in the fractional pulsatile PTH secretion (42^8.2 vs 18.3^3.9 pg/ml per min, P ¼ 0.006) in glucocorticoid-treated vs normal subjects. Mean overall PTH concentration, as well as mean integrated area, was similar among normal and glucocorticoid-treated subjects.Conclusions: These results demonstrate, for the first time, that chronic glucocorticoid treatment induces a redistribution of spontaneous PTH secretory dynamics by reducing the amount released in tonic fashion and increasing the amount released as pulses.

Glucocorticosteroid-induced osteoporosis in adult primiparous Göttingen miniature pigs: effects on bone mineral and mineral metabolism

“…Pearce et al (45) concluded that, rather than causing bone loss, PTH may be suppressed as a consequence of lost bone because of illness and immobility. Recently, it was shown that GC reduced the PTH tonic secretory rate and increased the fractional pulsatile PTH secretion, although the overall PTH concentration was similar among normal and GC-treated subjects (6). This indicated that a significant secondary hyperparathyroidism was not involved.…”

High-dose glucocorticoids increase serum levels of soluble IL-6 receptor α and its ratio to soluble gp130: an additional mechanism for early increased bone resorption

“…In fact, studies investigating serum PTH levels in GC-treated patients have yielded inconsistent results (29), possibly due to the fact that single random measurements do not reflect the overall pattern of PTH secretion. Bonadonna et al have recently shown that GC treatment induces a redistribution of spontaneous PTH secretory dynamics by reducing the amount released in tonic fashion and increasing the amount released as pulses (30).…”

Glucocorticoid-Induced osteoporosis: clinical and therapeutic aspects

“…While these actions may theoretically lead to a secondary increase in parathyroid hormone concentrations, most evidence now points away from that mechanism (18). On the other hand, there may be subtle, but important effects of glucocorticoids on PTH secretory dynamics, with a decrease in the tonic release of PTH and an increase in pulsatile bursts of the hormone (19). These changes may lead to adverse effects on bone metabolism (20), not unlike potential effects of PTH in postmenopausal osteoporosis (21).…”