scholarly journals TRH Test in Patients with Diabetes Mellitus Type 1 and/or Autoimmune Thyroiditis. Changes in the Pituitary –Thyroid Axis, Reverse T3, Prolactin and Growth Hormone Levels

2008 ◽  
pp. S109-S117
Author(s):  
E Orlická ◽  
K Vondra ◽  
M Hill ◽  
J Skibová ◽  
I Šterzl ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Autoimmune Thyroiditis ◽  
Autoimmune Diabetes ◽  
Diabetes Mellitus Type 1 ◽  
Free Triiodothyronine ◽  
Reverse T3 ◽  
Pituitary Thyroid Axis ◽  
Significant Impairment ◽  
Thyroid Axis

The response of the pituitary- thyroid axis, reverse triiodothyronine (rT3), prolactin, and growth hormone (GH) levels following TRH stimulus (Relefact TRH 200 microg 2 amp. i.v.) was examined in patients with autoimmune diabetes type 1 (DM1, n=30), with autoimmune thyroiditis (AT, n=25), and with concurrent DM1 and AT (n=22) to evaluate the influence of DM1 and AT of autoimmune pathogenesis on the above-mentioned hormonal parameters. Statistical analysis (ANOVA) showed that: a) the response of TSH did not differ from control groups (C); b) free triiodothyronine (fT3), free thyroxine (fT4) and their ratio in DM1, DM1+AT and C rose in 120 and 180 min, while a similar increase was not seen in AT (p<0.000001); c) rT3 was not present in any group, with rT3 levels higher in AT (p<0.00002) and lower in DM1 (p<0.02); d) the response of GH had a paradoxical character in some patients in all groups, most often in DM1 (52 %, DM1 vs C, p <0.01). The characteristic response difference was not in the peak GH level, but the delayed return to basal levels in DM1 (p<0.0001) and an abrupt one in AT (p<0.0001). The major findings in DM1 were the differences in GH response, while significant impairment of pituitary-thyroid axis and PRL response to TRH was absent. AT was associated with impairment of TRH stimulated fT3, fT4, fT3/fT4 response and changes in rT3 levels, in spite of preserved TRH-stimulated TSH secretion. GH response in AT patients was also altered.

scholarly journals The pituitary-thyroid axis in healthy men living under subarctic climatological conditions

2001 ◽  
Vol 169 (1) ◽  
pp. 195-203 ◽  
Author(s):  
J Hassi ◽  
K Sikkila ◽  
A Ruokonen ◽  
J Leppaluoto
Keyword(s):  
Thyroid Hormones ◽  
Climatic Factors ◽  
Feedback Mechanism ◽  
Free Triiodothyronine ◽  
Serum Free ◽  
Healthy Men ◽  
Non Invasive ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
Serum Tsh

In order to evaluate the effects of climatic factors on the secretion of thyroid hormones and TSH in a high latitude population, we have taken serum and urine samples from 20 healthy men from northern Finland (67 degrees -68 degrees N) every 2 months for a period of 14 months. Serum free triiodothyronine (T(3)) levels were lower in February than in August (3.9 vs 4.4 pmol/l, P<0.05) and TSH levels were higher in December than during other months (2.1 vs 1.5-1.7 mU/l, P<0.01). Serum total and free thyroxine (T(4)), total T(3) and reverse T(3) levels and urinary T(4) levels were unchanged. Urinary T(3) levels were significantly higher in winter than in summer. Serum free T(3) correlated highly significantly with the outdoor temperature integrated backwards weekly for 7-56 days (r=0.26 for 1-56 days) from the day when the blood samples were taken. Serum TSH did not show any significant correlation with the thyroid hormones or with the integrated temperature of the previous days, but it did show an inverse and significant correlation (r=-0.31) with the ambient luminosity integrated backwards for 7 days from the day when the blood sample was taken. The gradually increasing correlation between outdoor temperatures and serum free T(3) suggests that the disposal of thyroid hormones is accelerated in winter, leading to low serum free T(3) levels and a high urinary free T(3) excretion. Since there was no correlation between thyroid hormones and serum TSH, the feedback mechanism between TSH and thyroid hormones may not be the only contributing factor, and other factors such as ambient luminosity may at least partly determine serum TSH in these conditions. Also urinary free T(3) appears to be a novel and non-invasive indicator for thyroid physiology.

Pituitary-thyroid axis, prolactin and growth hormone in patients with acute stroke

1990 ◽  
Vol 228 (3) ◽  
pp. 287-290 ◽  
Author(s):  
T. OLSSON ◽  
K. ASPLUND ◽  
E. HÄGG
Keyword(s):  
Growth Hormone ◽  
Acute Stroke ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis

scholarly journals Liver at the nexus of rat postnatal HPA axis maturation and sexual dimorphism

2021 ◽  
Vol 248 (1) ◽  
pp. R1-R17
Author(s):  
Julia N C Toews ◽  
Geoffrey L Hammond ◽  
Victor Viau
Keyword(s):  
Sexual Dimorphism ◽  
Hpa Axis ◽  
Mammalian Species ◽  
Normal Function ◽  
Expression Of Genes ◽  
Corticosteroid Binding Globulin ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
Context Specific

Normal function of the hypothalamic–pituitary–adrenal (HPA) axis is critical for survival, and its development is choreographed for age-, sex- and context-specific actions. The liver influences HPA ontogeny, integrating diverse endocrine signals that inhibit or activate its development. This review examines how developmental changes in the expression of genes in the liver coordinate postnatal changes in multiple endocrine systems that facilitate the maturation and sexual dimorphism of the rat HPA axis. Specifically, it examines how the ontogeny of testicular androgen production, somatostatin-growth hormone activities, and hypothalamic-pituitary-thyroid axis activity intersect to influence the hepatic gene expression of insulin-like growth factor 1, corticosteroid-binding globulin, thyroxine-binding globulin, 11β-hydroxysteroid dehydrogenase type 1 and 5α-reductase type 1. The timing of such molecular changes vary between mammalian species, but they are evolutionarily conserved and are poised to control homeostasis broadly, especially during adversity. Importantly, with the liver as their nexus, these diverse endocrine systems establish the fundamental organization of the HPA axis throughout postnatal development, and thereby ultimately determine the actions of glucocorticoids during adulthood.

The hypothalamic-pituitary-thyroid axis in Type 1 diabetes: influence of diabetic metabolic control

1984 ◽  
Vol 106 (1) ◽  
pp. 92-96 ◽  
Author(s):  
I. A. MacFarlane ◽  
M. C. Sheppard ◽  
E. G. Black ◽  
S. Gilbey ◽  
A. D. Wright
Keyword(s):  
Metabolic Control ◽  
Thyroid Function ◽  
Fasting Blood Glucose ◽  
Type I ◽  
Poor Metabolic Control ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
Insulin Dependent ◽  
Serum Tsh

Abstract. The influence of diabetic metabolic control on indices of thyroid function was studied in 9 euthyroid, insulin-dependent (Type 1) diabetics. During chronic poor metabolic control (mean fasting blood glucose 13 mmol/l and HbA1 concentrations 14.7%) serum T3 concentrations were low (P < 0.01) while serum T4 and basal TSH concentrations were normal. After 6–8 weeks of improved metabolic control, mean HbA1 concentrations had fallen to 10.7% (P < 0.01) and serum T3 concentrations had increased into the normal range. Serum T4 and basal TSH concentrations were unchanged. The serum TSH response to iv TRH remained normal throughout the study. In Type I diabetics, with chronic poor metabolic control, the serum T4 concentration and the TSH response to TRH are therefore appropriate indicators of thyroid function.

scholarly journals Epigenome-Wide Association Study of Thyroid Function Traits Identifies Novel Associations of fT3 With KLF9 and DOT1L

2021 ◽  
Author(s):  
Nicole Lafontaine ◽  
Purdey J Campbell ◽  
Juan E Castillo-Fernandez ◽  
Shelby Mullin ◽  
Ee Mun Lim ◽  
...  
Keyword(s):  
Association Study ◽  
Thyroid Function ◽  
Positive Association ◽  
Free Triiodothyronine ◽  
Illumina Humanmethylation450 ◽  
Pituitary Thyroid Axis ◽  
Illumina Humanmethylation450 Beadchip ◽  
Thyroid Axis ◽  
Advanced Knowledge ◽  
Novel Associations

Abstract Context Circulating concentrations of free triiodothyronine (fT3), free thyroxine (fT4), and thyrotropin (TSH) are partly heritable traits. Recent studies have advanced knowledge of their genetic architecture. Epigenetic modifications, such as DNA methylation (DNAm), may be important in pituitary-thyroid axis regulation and action, but data are limited. Objective To identify novel associations between fT3, fT4, and TSH and differentially methylated positions (DMPs) in the genome in subjects from 2 Australian cohorts. Method We performed an epigenome-wide association study (EWAS) of thyroid function parameters and DNAm using participants from: Brisbane Systems Genetics Study (median age 14.2 years, n = 563) and the Raine Study (median age 17.0 years, n = 863). Plasma fT3, fT4, and TSH were measured by immunoassay. DNAm levels in blood were assessed using Illumina HumanMethylation450 BeadChip arrays. Analyses employed generalized linear mixed models to test association between DNAm and thyroid function parameters. Data from the 2 cohorts were meta-analyzed. Results We identified 2 DMPs with epigenome-wide significant (P &lt; 2.4E−7) associations with TSH and 6 with fT3, including cg00049440 in KLF9 (P = 2.88E−10) and cg04173586 in DOT1L (P = 2.09E−16), both genes known to be induced by fT3. All DMPs had a positive association between DNAm and TSH and a negative association between DNAm and fT3. There were no DMPs significantly associated with fT4. We identified 23 differentially methylated regions associated with fT3, fT4, or TSH. Conclusions This study has demonstrated associations between blood-based DNAm and both fT3 and TSH. This may provide insight into mechanisms underlying thyroid hormone action and/or pituitary-thyroid axis function.

Hypothalamus-pituitary-thyroid axis interactions with pineal gland in the rat.

1979 ◽  
Vol 236 (4) ◽  
pp. E416 ◽  
Author(s):  
G L Brammer ◽  
J E Morley ◽  
E Geller ◽  
A Yuwiler ◽  
J M Hershman
Keyword(s):  
Pineal Gland ◽  
Serum Levels ◽  
Thyroid Stimulating Hormone ◽  
Free Triiodothyronine ◽  
Prolactin Release ◽  
Free Thyroxine Index ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
Melatonin Production

We examined in the rat several possible relationships between the pineal gland and the hypothalamus-pituitary-thyroid axis. The pineal gland, the retina, and the hypothalamus exhibited a diurnal rhythm in thyrotropin-releasing hormone (TRH) content with peak values occurring around 1200 h. This rhythm in the hypothalamus was abolished by constant light but was not affected by pinealectomy. Nor did pinealectomy affect hypothalamic TRH content, pituitary content of thyroid-stimulating hormone (TSH) or prolactin; serum levels of (TSH), triiodothyronine (T3), or thyroxine (T4), or serum free-thyroxine index; or free-triiodothyronine index. Melatonin did not affect TSH or prolactin release from the anterior pituitary or TRH release from the hypothalamus in vitro. Isoproterenol did not affect the TRH content of pineal glands in vitro; nor did TRH or T3 affect basal or stimulated activities of serotonin N-acetyltransferase, the presumed controlling enzyme in melatonin production. We found no evidence for significant interactions between the pineal gland and the hypothalamus-pituitary-thyroid axis.

Alteration of thyroid function in the early stage of subacute thyroiditis

1980 ◽  
Vol 95 (4) ◽  
pp. 479-484 ◽  
Author(s):  
G. Madeddu ◽  
M. Langer ◽  
C. Costanza ◽  
A. R. Casu ◽  
M. L. Arras ◽  
...  
Keyword(s):  
Early Stage ◽  
Subacute Thyroiditis ◽  
Cellular Damage ◽  
Normal Range ◽  
Free Triiodothyronine ◽  
Normal Limits ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
Antithyroglobulin Antibodies ◽  
Unilateral Involvement

Abstract. Measurement of serum triiodothyronine (T3), thyroxine (T4), free triiodothyronine (FT3), free thyroxine (FT4), thyroxine-binding-globulin (TGB), antithyroglobulin antibodies (anti-hTg), thyroid 131I uptake and scanning was performed on 12 patients during the early phase of subacute thyroiditis. Serum thyrotropin (TSH) was measured during baseline conditions and following administration of synthetic thyrotropin-releasing-hormone (TRH). The stimulation with exogenous TSH was performed on 7 subjects. 131I uptake was depressed in all patients including those with solitary nodules. Free and total hormone concentrations were elevated in the three cases with diffuse gland involvement, whereas an increase of T3 alone was present in 3 patients with unilobar involvement. In the latter group and in the 2 patients with a nodular form T4, FT3 and FT4 levels were within normal limits. Interruption of the pituitary-thyroid feed-back mechanism with absence of thyrotropin response to TRH occurred in 11 patients, independent of whether thyroid hormone concentrations were elevated or normal. In one patient only with unilateral involvement, TSH responsiveness to TRH was normal while 131I uptake was not raised by exogenous TSH, indicating diffuse cellular damage. The normal values of FT3 and FT4 found in patients with normal T3 and T4 levels seem to exclude the possibility that the free hormones are responsible for the interrupted feed-back which represents the main cause of suppressed iodine uptake. However, it is possible that the pituitary-thyroid axis is responding to transient or light increases of free and total T3 and T4 still within their 'normal range'.

scholarly journals High-Fat Diet Increases Thyrotropin and Oxygen Consumption without Altering Circulating 3,5,3′-Triiodothyronine (T3) and Thyroxine in Rats: The Role of Iodothyronine Deiodinases, Reverse T3 Production, and Whole-Body Fat Oxidation

Endocrinology ◽  
2010 ◽  
Vol 151 (7) ◽  
pp. 3460-3469 ◽  
Author(s):  
R. L. Araujo ◽  
B. M. Andrade ◽  
A. S. Padrón ◽  
M. P. Gaidhu ◽  
R. L. S. Perry ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Energy Balance ◽  
Fat Oxidation ◽  
Whole Body ◽  
Positive Energy ◽  
High Fat ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis

This study investigated the effects of obesity induced by high-fat (HF) diet on thyroid function and whole-body energy balance. To accomplish that, we assessed the effects of 8 wk of HF diet on several parameters of hypothalamus-pituitary-thyroid axis function. Serum total T4 and T3, rT3, and TSH, the activity of type 1 and type 2 deiodinases in central and peripheral tissues were determined. Also, we measured in vivo energy balance, substrate partitioning, and markers of leptin resistance. Here we provide novel evidence that prolonged positive energy balance acquired by feeding a HF diet induced hyperactivation of the hypothalamus-pituitary-thyroid axis, which was characterized by 2.24-, 1.6-, and 3.7-fold elevations in hypothalamic TRH expression, thyroid iodide uptake, and serum TSH, respectively. Serum T4 and T3 were normal together with augmented deiodinase type 1 activity in liver (1.3-fold) and kidney (1.2-fold) and increased (1.5-fold) serum rT3 in HF rats. Despite no increase in circulating levels of T3 and T4, whole-body oxygen consumption was increased, and substrate metabolism was shifted toward fat oxidation in HF rats. These in vivo metabolic adjustments were mainly driven by the fat content of the diet. Furthermore, spontaneous dark cycle physical activity was reduced by 30% in rats fed a HF diet, which limited energy expenditure and favored the development of obesity. Our findings provide new insight into the endocrine and physiological mechanisms that underlie the alterations in thyroid hormone availability, energy balance, and metabolic partitioning in HF diet-induced obesity.

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