Markers of bone metabolism during short-term administration of thyroxine in healthy volunteers.
We investigated the influence of L-thyroxine (L-T4) treatment over 3 weeks on biochemical markers of bone turnover in 12 healthy young men (age 25.6 +/- 1.4 years, BMI: 22.6 +/- 2.5 kg/m2). Serum parameters indicating bone formation [bone Gla protein (BGP), carboxyterminal propeptide of type I procollagen (PICP), and bone-specific alkaline phosphatase (BAP)] and bone resorption [cross-linked carboxyterminal telopeptide of type I collagen (ICTP) and the urinary excretion of pyridinoline (Pyr) and deoxypyridinoline (D-Pyr)] were measured before and after three weeks of treatment with 300 micrograms L-T4/d. T3 and T4 significantly increased and TSH decreased to almost undetectable levels even when measured with a third generation TSH assay. Markers of bone formation showed variable responses with a small but significant increase in BGP but not in PICP or BAP. In contrast, all parameters of bone resorption increased significantly with a good correlation between D-Pyr excretion and the serum parameter ICTP (r = 0.78, p < 0.0001). These changes in bone-turnover markers were not necessarily paralleled by comparable increments of other markers of tissue thyrotoxicosis (SHBG, pulse rate, VO2), suggesting a variability in tissue sensitivity. These rapid responding parameters, especially in the easily obtainable serum parameter ICTP, might be valuable tools in the evaluation of several states of thyroxine excess.
Frevert
E U
EU
Dept. Klin. Endokrinologie, Med. Hochschule Hannover, Germany.
Biester
A
A
Müller
M J
MJ
Schmidt-Gayk
H
H
von zur Mühlen
A
A
Brabant
G
G
D000328:Adult; D000596:Amino Acids / Q000652:urine; D015415:Biomarkers; D001862:Bone Resorption / Q000503:physiopathology; D001842:Bone and Bones / Q000187:drug effects* / Q000378:metabolism*; D003094:Collagen / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D015675:Osteocalcin / Q000378:metabolism; D010012:Osteogenesis / Q000502:physiology; D010446:Peptide Fragments / Q000378:metabolism; D011347:Procollagen / Q000378:metabolism; D012016:Reference Values; D013974:Thyroxine / Q000008:administration & dosage / Q000494:pharmacology*; D013997:Time Factors
D000596:Amino Acids; D015415:Biomarkers; D010446:Peptide Fragments; D011347:Procollagen; C042813:procollagen type I carboxy terminal peptide; D015675:Osteocalcin; C015484:pyridinoline; C036020:deoxypyridinoline; D003094:Collagen; D013974:Thyroxine