Download PDF
Horm Metab Res 1977; 9(2): 141-146
DOI: 10.1055/s-0028-1093563
Originals

© Georg Thieme Verlag KG Stuttgart · New York

TBG-Dependency of Age Related Variations of Thyroxine and Triiodothyronine

R. -D. Hesch , J.  Gatz , H.  Jüppner , P.  Stubbe
  • Department Innere Medizin, Abteilung für Klinische Endokrinologie, Medizinische Hochschule Hannover und Universitäts-Kinderklinik, Göttingen, Germany
Further Information

Publication History

Publication Date:
23 December 2008 (online)

Also available at
  PDF Download  Permissions and Reprints

Abstract

Thyroxine (T4), triiodothyronine (T3) and thyroxine-binding globulin (TBG) were determined in healthy individuals ranging in age from newborn to 95 years. T4: 10.25 ± 1.62 µg/100 ml, T3: 1.62 ± 0.35 ng/ml and TBG: 1.34 ± 0.15 mg/100 ml, were found elevated until puberty compared to a middle age group with T4: 7.27 ± 2.26 µg/100 ml, T3: 1.15 ± 0.24 ng/ml and TBG: 0.98 ± 14 mg/100 ml. T4 and T3 followed almost TBG concentration. In old age is dissociation between T4: 5.79 ± 1.56 µg/100 ml, T3: 0.79 ± 0.21 ng/ml and TBG: 1.28 ± 0.15 mg/100 ml was found. Except for old age the ratio T4/TBG and T3/TBG minimized the age dependent variation of T4 and T3 and reduced the coefficient of variance from 26% to 17.7% for T4 and from 26.5 to 25% for T3. Age reduction of T4/TBG is 15% and of T3/TBG 13% respectively more pronounced than for T4 and T3 alone. These data indicate:
1) age related variations of T4 and T3 due to age dependency of TBG,
2) deviation of T4 and T3 values in old age from that expected by their TBG levels and
3) the importance of the routine use of hormone/TBG ratio.

Key words

T4 - T3 - Age Relation - TBG