Naslov
Effects of TSH and calcitriol on bone metabolism: in vivo and in vitro study

Autori
Dumić-Čule, Ivo ; Rogić, Dunja ; Ježek, Damir ; Grgurević, Lovorka ; Vukičević, Slobodan

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Bone abstracts / - , 2014

Skup
41. European Symposium on Calcified Tissues

Mjesto i datum
Prag, Češka Republika, 17.05.2014. - 20.05.2014

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
thyroid-stimulating hormone; microCT; bone formation

Sažetak
Thyroid-stimulating hormone (TSH) exerts both antiresorptive and anabolic effects on bone remodeling in aged ovariectomized rats and TSH -/- mice, supported by clinical results demonstrating that low TSH level is associated with increased bone loss. To further explore the effect of TSH on bone metabolism we here introduced a rat model with removed thyroid and parathyroid glands to obtain low serum concentrations of thyroid and parathyroid hormone, calcitonin and 1, 25(OH)2D3 (approval for the experiment was obtained from ethical committee of University of Zagreb). Surgery resulted in hypocalcemia, low parathyroid and thyroid hormone, 1, 25(OH)2D3, C-telopeptide and osteocalcin serum level. Intermittent administration of TSH resulted in a further decrease of serum calcium and decreased level of serum C-telopeptide due to the suppression of bone resorption, while in the same animals osteocalcin in serum was higher indicating an increased bone formation rate. MicroCT analyses of the distal femur and proximal tibia showed that rats treated with 1, 25(OH)2D3 alone or in a combination with TSH had an increased trabecular bone volume, and enhanced trabecular bone quality. Biomechanical testing of the trabecular bone showed an increased maximal load for 105% and 235%, respectively, in rats treated with 1, 25(OH)2D3 alone, or in a combination with TSH. Rats treated with TSH had a significantly decreased number of osteoclasts in comparison to TPTx control animals. The decline of the osteoclast number was even greater in rats treated with a combination of TSH and 1, 25(OH)2D3, despite the fact that 1, 25(OH)2D3 increased the number of osteoclasts. Addition of TSH to osteoblasts increased the production of the bone specific alkaline phosphatase and had a synergistic effect when combined with 1, 25(OH)2D3. We suggest that TSH independently of calciotropic hormones suppressed bone resorption and stimulated bone formation, while in combination with 1, 25(OH)2D3 acted synergistically on bone formation resulting in an increased bone volume.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti, Kliničke medicinske znanosti, Farmacija

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