Interrelationships among body mass, thyrotropin, thyroid hormones, and thyroid-hormone binding proteins in healthy 70-year-old men.

1984 ◽  
Vol 30 (5) ◽  
pp. 681-686 ◽  
Author(s):  
S Edén ◽  
R Jagenburg ◽  
G Lindstedt ◽  
P A Lundberg ◽  
D Mellström
Keyword(s):  
Body Mass Index ◽  
Thyroid Hormone ◽  
Body Mass ◽  
Binding Proteins ◽  
Dominant Role ◽  
Negative Relationship ◽  
Feedback Regulation ◽  
Hormone Binding ◽  
Free T4 ◽  
Old Men

Abstract In a previous study of a representative population of 460 men of age 70, we found that the free thyroxin (free T4) concentration was negatively correlated to body mass. In the present study we analyzed other indicators of thyroid function in relation to body mass and body mass index in 181 individuals without any disease or medication influencing thyroidal homeostasis or body mass. There was a significant negative relationship between body mass and body mass index and free T4, total T4, and 3,3',5'-triiodothyronine (rT3). Thus, individuals with high body mass normally had lower circulating concentrations of these hormones than lean individuals, whereas there was no such relationship for thyrotropin or 3,5,3'-triiodothyronine (T3). The thyroid-hormone binding proteins (thyroxin-binding globulin, prealbumin, and albumin) did not correlate with body mass or body mass index. As expected, thyroxin-binding globulin correlated with T4, T3, and rT3, but not with free T4 or thyrotropin. Concentrations of serum albumin correlated with T3 and rT3 concentrations but not with free T4, T4, or thyrotropin concentrations. Thyrotropin concentrations correlated negatively with free T4, T4, and rT3, but not with T3, indicating that circulating T4 plays the dominant role in feedback regulation of thyrotropin in healthy individuals.

Indirect estimation of thyroid hormone-binding proteins to calculate free thyroxine index: comparison of nonisotopic methods that use labeled thyroxine ("T-uptake")

1995 ◽  
Vol 41 (1) ◽  
pp. 41-47 ◽  
Author(s):  
J D Faix ◽  
H N Rosen ◽  
F R Velazquez
Keyword(s):  
Thyroid Hormone ◽  
Binding Proteins ◽  
Free Thyroxine ◽  
Reference Ranges ◽  
Hormone Binding ◽  
Free T4 ◽  
Nonthyroidal Illness ◽  
Free Thyroxine Index ◽  
Uptake Method ◽  
Hypothyroid Patients

Abstract There are many alternative ways of estimating free thyroxine (T4) when thyrotropin screening results are abnormal. In addition to free T4 immunoassays, the menu of most automated immunoassay instruments includes a nonisotopic version of the original triiodothyronine (T3)-uptake assay called "T-uptake." We evaluated the ability of five such assays (Access, ES-300, IMx, Magnum Opus, and Stratus) to accurately estimate the free thyroxine index (FTI) in euthyroid, hyperthyroid, and hypothyroid patients with abnormal concentrations of thyroid hormone-binding proteins, and in patients with nonthyroidal illness. For comparison, we calculated a similar FTI, using either T3-uptake or direct measurement of thyroxine-binding globulin (TBG). Euthyroid reference ranges were comparable. Of euthyroid patients with increased TBG, 12-32% and 5-20% had increased or suppressed FTI, respectively, depending on the T-uptake method used. Except for IMx, 6-35% of hypothyroid patients with increased TBG had inappropriately increased FTI. Patients with nonthyroidal illness had comparable results regardless of the method used, and T-uptake methods were variably affected by known inhibitors of thyroid hormone binding. The most reliable T-uptake method appeared to be the IMx, which, despite claims that it measures all thyroid hormone-binding proteins, correlated best with TBG concentrations.

Uptake of thyroxine by the perfused rat liver: implications for the free hormone hypothesis

1988 ◽  
Vol 255 (2) ◽  
pp. E110-E119 ◽  
Author(s):  
C. M. Mendel ◽  
R. R. Cavalieri ◽  
R. A. Weisiger
Keyword(s):  
Thyroid Hormone ◽  
Rat Liver ◽  
Rate Constants ◽  
Binding Proteins ◽  
Human Thyroid ◽  
Plasma Binding ◽  
Perfused Rat Liver ◽  
Hormone Binding ◽  
Free T4 ◽  
Hepatic Cells

To investigate the mechanism by which thyroxine (T4) in plasma enters hepatic cells, we measured the rate constants for uptake of free T4 by the perfused rat liver and for dissociation of T4 from its plasma binding proteins. Quantitative autoradiography of liver lobules after perfusion with [125I]T4 indicated an apparent rat constant for removal of free T4 from the sinusoids of at least 1.1 +/- 0.2 s-1. Single-pass extraction of T4 from human serum was 10.6 +/- 1.7% at physiological flow rates (1 ml.min-1.g liver-1). Rate constants for dissociation of T4 from plasma binding proteins at 37 degrees C (determined by rapid filtration) were 0.017 +/- 0.002 s-1 for human thyroid hormone-binding globulin, 0.080 +/- 0.015 s-1 for human thyroid hormone-binding prealbumin, and greater than 0.5 s-1 for human albumin. To investigate the factors that determine the concentration of T4 within hepatic cells, we analyzed the above data together with data reported in the literature on the equilibrium-binding constants and the rate constant for cellular metabolism of T4. Analysis of all of these data using a previously published mathematical model leads to the following conclusions for the physiological state: 1) metabolism, not uptake, is rate limiting to removal of T4 from plasma by the liver; 2) binding equilibrium is present in the intrahepatic plasma; 3) intracellular T4 is in equilibrium with the free T4 pool in plasma (and maintenance of this equilibrium may be an important function of plasma thyroid hormone-binding proteins); and 4) the concentration of T4 within the liver is proportional to the concentration of free T4 in the plasma. Our data do not allow us to determine definitively whether hepatic uptake of T4 occurs only from the free T4 pool in plasma or also from the protein-bound pool by interaction of one or more of the binding proteins with the liver cell. However, mathematical analysis indicates that this distinction is irrelevant to steady-state intracellular hormone concentrations when equilibrium exists between the plasma and cytosolic pools of hormone.

scholarly journals Studies on Cytosol Thyroid Hormone Binding Proteins in Rat Liver

1987 ◽  
Vol 63 (1) ◽  
pp. 69-76
Author(s):  
Masataka NANNO ◽  
Hirotoshi NAKAMURA ◽  
Satoshi HAMADA ◽  
Teruya YOSHIMI ◽  
Hiroo IMURA ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Rat Liver ◽  
Binding Proteins ◽  
Hormone Binding

Concentrations of sex-hormone binding globulin and corticosteroid binding globulin in serum in relation to cardiovascular risk factors and to 12-year incidence of cardiovascular disease and overall mortality in postmenopausal women.

1986 ◽  
Vol 32 (1) ◽  
pp. 146-152 ◽  
Author(s):  
L Lapidus ◽  
G Lindstedt ◽  
P A Lundberg ◽  
C Bengtsson ◽  
T Gredmark
Keyword(s):  
Risk Factors ◽  
Cardiovascular Disease ◽  
Body Mass Index ◽  
Body Mass ◽  
Significant Risk ◽  
Sex Hormone ◽  
Sex Hormone Binding Globulin ◽  
Hormone Binding ◽  
Corticosteroid Binding Globulin ◽  
Overall Mortality

Abstract We determined sex-hormone binding globulin (SHBG) and corticosteroid binding globulin (CBG) by radioimmunoassay of serum samples from a group of 253 women, who were 54 or 60 years old when first studied in 1968-69. The SHBG concentration was highly significantly and inversely related to body mass, body mass index, waist-to-hip circumference ratio, and serum triglyceride concentration; CBG concentration was inversely related to body mass and body mass index. The concentration of neither protein was related to whether or not the subject smoked. Decrease in the concentration of SHBG, but not of CBG, was a significant risk factor for 12-year overall mortality. The plot of the 12-year incidence of myocardial infarction vs SHBG concentration was U-shaped. We recommend that SHBG be included when serum androgens or estrogens are being evaluated as risk factors for cardiovascular disease and death.

scholarly journals Studies on Cytosol Thyroid Hormone Binding Proteins in Rat Liver

1987 ◽  
Vol 63 (1) ◽  
pp. 77-86
Author(s):  
Masataka NANNO ◽  
Hirotoshi NAKAMURA ◽  
Satoshi HAMADA ◽  
Teruya YOSHIMI ◽  
Hiroo IMURA ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Rat Liver ◽  
Binding Proteins ◽  
Hormone Binding

scholarly journals LOW BODY MASS INDEX IS ASSOCIATED WITH HIGHER COMPLEXITY OF CARE IN OLDEST OLD MEN WITH DYNAPENIA

2017 ◽  
Vol 1 (suppl_1) ◽  
pp. 382-382
Author(s):  
Y. Wang ◽  
C. Liang ◽  
M. Chou ◽  
Y. Lin ◽  
H. Lam
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Oldest Old ◽  
Low Body Mass Index ◽  
Old Men

scholarly journals Genetic Damage in Workers from the Rare Metal Ore Production Region

Minerals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 135
Author(s):  
Dina Petrashova ◽  
Alla Martynova ◽  
Vladimir Megorskiy
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Negative Relationship ◽  
Rare Metal ◽  
Exposed Group ◽  
The Body ◽  
Buccal Epithelium ◽  
Production Region ◽  
Micronucleus Frequency ◽  
Murmansk Region

The aim of this study was to assess the genotoxic and cytotoxic effects that occur in miners working underground in rare metal ore mines at ionizing radiation levels within the maximum permissible concentration (MPC) standards using the buccal micronucleus cytome (BMCyt) assay. At the same time, we attempted to identify possible relationships between cytogenetic abnormalities in the buccal epithelium and such physiological indicators as cardiodynamics and the body mass index. The study involved a total of 269 individuals, 236 miners working underground in production related to the mining and enrichment of loparite ores and 33 non-exposed individuals (Russia, Murmansk region). Buccal micronucleus cytome assay and heart rate variability parameters were used. Micronucleus frequency was revealed to be a higher in the exposed group (8.3 ± 1.08‰) than in the non-exposed group (3.3 ± 0.49‰). The repair index showed a statistically significant increase in the non-exposed group (14.9 ± 2.90) compared with the exposed group (6.1 ± 0.74). The frequency of nuclear protrusions correlates significantly with the body mass index in the young miners (≤30 years (r = 0.45)). There is a negative relationship between the micronucleus frequency and the level of organism adaptation (r = −0.24), the vegetative regulation rate (r = −0.20) and the psycho-emotional state (r = −0.30) for miners older than 30 years. The results testify to the possible induction of clastogenic effects and a decrease in the level of reparation in the buccal epithelium cells due to the exposure of a various of production factors in the extraction of loparite ore.

Sign in / Sign up

Export Citation Format

Share Document