The effects of recombinant human TSH on bone turnover in patients after thyroidectomy.
Thyrotropin receptors are expressed in several extrathyroidal tissues including bone. We investigated whether the increase of thyroid-stimulating hormone (TSH) levels, under stable thyroid hormone levels, affects the bone markers. Thirty-two postmenopausal women, with papillary thyroid carcinoma, previously treated with near-total thyroidectomy and I131 remnant ablation underwent routine evaluation for residual disease by using injections of recombinant human TSH (rhTSH) without withdrawal from thyroxine therapy. Changes in TSH levels and various serum and urine markers of bone metabolism were followed before and 1, 2, 5, and 7 days after the rhTSH injections. A transient, significant decrease in serum calcium and urinary excretion of C- and N-terminal telopeptides of type I collagen was observed after the injections of rhTSH. Serum parathyroid hormone (PTH) started to rise along with TSH, but a significant increase of PTH was only reached on Day 5 when the TSH concentration had fallen more than 80% of the peak value. Bone alkaline phosphatase and osteocalcin did not show any significant change over time. There was no significant correlation between TSH concentration and the various parameters we measured. The study provides evidence that rhTSH produces a transient inhibition of bone resorption, as well as an attenuation of osteoblast response in spite of the PTH activation. Additional studies are needed to resolve the mechanisms by which TSH alters the response of the bone cells.
Karga
Helen
H
2nd Division of Endocrinology and Metabolism, Alexandra Hospital, Vas. Sofias and Lourou, 11528 Athens, Greece. hkarga@yahoo.gr
Papaioannou
Garyphallia
G
Polymeris
Antonis
A
Papamichael
Konstantinos
K
Karpouza
Angeliki
A
Samouilidou
Elizabeth
E
Papaioannou
Panayotis
P
D000368:Aged; D015415:Biomarkers / Q000097:blood / Q000652:urine; D016723:Bone Remodeling / Q000187:drug effects*; D002118:Calcium / Q000097:blood / Q000652:urine; D002291:Carcinoma, Papillary / Q000532:radiotherapy / Q000601:surgery; D024042:Collagen Type I / Q000652:urine; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000188:drug therapy; D008875:Middle Aged; D018365:Neoplasm, Residual / Q000175:diagnosis; D010281:Parathyroid Hormone / Q000097:blood; D010455:Peptides / Q000652:urine; D010758:Phosphorus / Q000097:blood / Q000652:urine; D011994:Recombinant Proteins / Q000494:pharmacology; D013964:Thyroid Neoplasms / Q000532:radiotherapy / Q000601:surgery; D013965:Thyroidectomy; D013972:Thyrotropin / Q000097:blood / Q000493:pharmacokinetics / Q000494:pharmacology*; D013974:Thyroxine / Q000627:therapeutic use; D013997:Time Factors
D015415:Biomarkers; D024042:Collagen Type I; D010281:Parathyroid Hormone; D010455:Peptides; D011994:Recombinant Proteins; C052929:collagen type I trimeric cross-linked peptide; D010758:Phosphorus; D013972:Thyrotropin; D013974:Thyroxine; D002118:Calcium