STUDIES ON THE ORIGIN OF ALTERED THYROID HORMONE LEVELS IN THE BLOOD OF RATS DURING COLD EXPOSURE

1979 ◽  
Vol 91 (3) ◽  
pp. 473-483 ◽  
Author(s):  
C. van Hardeveld ◽  
M. J. Zuidwijk ◽  
A. A. H. Kassenaar
Keyword(s):  
Drinking Water ◽  
Thyroid Hormone ◽  
Food Intake ◽  
Cold Exposure ◽  
Plasma Levels ◽  
Plasma Concentrations ◽  
Contributory Factor ◽  
Change Pattern ◽  
Thyroid Hormone Levels ◽  
Altered Thyroid

ABSTRACT Rats were exposed to cold (4°C) for 1 and 4 weeks. The T4 plasma concentrations initially declined (24.5 ± 7.7 nmol/l) after 1 week but returned to normal levels after 4 weeks (52.9 ± 14.2 nmol/l). The T3 concentrations were elevated after both 1 and 4 weeks at 4°C (1.31 ± 0.21 and 1.38 ± 0.12 nmol/l, respectively). Control values (23°C) for T4 were 42.6 ± 10.3 and for T3 1.11 ± 0.13 nmol/l. Addition of 0.015 g KI/l to the drinking water prevented the T4 decrease in plasma after 1 week of cold exposure. No effect of iodide was observed at 23°C. The suppletion of KI did not change pattern of T3 increase after cold exposure. After 4 weeks of cold exposure the T4 levels of the iodide-supplemented animals did not differ from the non-supplemented group. No evidence was found that increased food intake is a contributory factor in the development leading to increased T3 plasma levels during cold exposure.

STUDIES ON THE ORIGIN OF ALTERED THYROID HORMONE LEVELS IN THE BLOOD OF RATS DURING COLD EXPOSURE

1979 ◽  
Vol 91 (3) ◽  
pp. 484-492 ◽  
Author(s):  
C. van Hardeveld ◽  
M. J. Zuidwijk ◽  
A. A. H. Kassenaar
Keyword(s):  
Thyroid Hormone ◽  
Cold Exposure ◽  
Plasma Levels ◽  
Dose Regimen ◽  
Sympathetic Activity ◽  
Chemical Sympathectomy ◽  
Hormone Levels ◽  
Thyroid Hormone Levels ◽  
Altered Thyroid

ABSTRACT The effect of sympathetic activity on T4 and T3 levels in cold-exposed rats was investigated. Administration of the highest dose of propranolol (2 mg/100 g b.w.) twice daily during 4 days decreased T4 and T3 concentrations in plasma of rats living at 23°C (T4 from 46.4 ± 2.6 to 25.8 ± 5.3 nmol/l and T3 from 1.08. ± 0.6 to 0.82 ± 0.12 nmol/l). No significant effect on T4 and T3 levels (49.0 ± 11.6 and 1.48 ± 0.16 n/mol, respectively) after the administration of the same dose regimen of propranolol was observed in rats exposed to cold for 4 weeks. T4 and T3 levels in rats exposed to cold for 4 weeks were not significantly altered 1 week after sympathectomy, while remaining in the cold. However, chemical sympathectomy before cold exposure delayed the cold induced T3 elevation occurring during the first week of cold exposure (controls: from 1.16 ± 0.19 to 1.44 ± 0.29 nmol/l; sympathectomized rats: from 1.07 ± 0.12 to 1.17 ± 0.22 nmol/l). After 2 weeks of cold exposure the T3 levels of controls and sympathectomized rats were not significantly different (controls: 1.45 ± 0.12 nmol/l, sympathectomized rats: 1.38 ± 0.15 nmol/l). No effect of sympathectomy was observed on T4 levels. These experiments show that the role of sympathetic activity in increasing T3 is not clear during cold exposure. They provide some evidence that sympathetic activity may play a role in the initiation of the process leading to increased T3 plasma levels during cold exposure.

scholarly journals Neuropeptide Y1 and Y5 Receptors Mediate the Effects of Neuropeptide Y on the Hypothalamic-Pituitary-Thyroid Axis

Endocrinology ◽  
2002 ◽  
Vol 143 (12) ◽  
pp. 4513-4519 ◽  
Author(s):  
Csaba Fekete ◽  
Sumit Sarkar ◽  
William M. Rand ◽  
John W. Harney ◽  
Charles H. Emerson ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Food Intake ◽  
Neuropeptide Y ◽  
Paraventricular Nucleus ◽  
Receptor Agonist ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
Ad Libitum ◽  
Thyroid Hormone Levels ◽  
Hpt Axis

Abstract Neuropeptide Y (NPY) is one of the most important hypothalamic-derived neuropeptides mediating the effects of leptin on energy homeostasis. Central administration of NPY not only markedly stimulates food intake, but simultaneously inhibits the hypothalamic-pituitary-thyroid axis (HPT axis), replicating the central hypothyroid state associated with fasting. To identify the specific NPY receptor subtypes involved in the action of NPY on the HPT axis, we studied the effects of the highly selective Y1 ([Phe7,Pro34]pNPY) and Y5 ([chicken pancreatic polypeptide1–7, NPY19–23, Ala31, Aib32 (aminoisobutyric acid), Q34]human pancreatic polypeptide) receptor agonists on circulating thyroid hormone levels and proTRH mRNA in hypophysiotropic neurons of the hypothalamic paraventricular nucleus. The peptides were administered continuously by osmotic minipump into the cerebrospinal fluid (CSF) over 3 d in ad libitum-fed animals and animals pair-fed to artificial CSF (aCSF)-infused controls. Both Y1 and Y5 receptor agonists nearly doubled food intake compared with that of control animals receiving aCSF, similar to the effect observed for NPY. NPY, Y1, and Y5 receptor agonist administration suppressed circulating levels of thyroid hormones (T3 and T4) and resulted in inappropriately normal or low TSH levels. These alterations were also associated with significant suppression of proTRH mRNA in the paraventricular nucleus, particularly in the Y1 receptor agonist-infused group [aCSF, NPY, Y1, and Y5 (density units ± sem), 97.2 ± 8.6, 39.6 ± 8.4, 19.9 ± 1.9, and 44.6 ± 8.4]. No significant differences in thyroid hormone levels, TSH, or proTRH mRNA were observed between the agonist-infused FSanimals eating ad libitum and the agonist-infused animals pair-fed with vehicle-treated controls. These data confirm the importance of both Y1 and Y5 receptors in the NPY-mediated increase in food consumption and demonstrate that both Y1 and Y5 receptors can mediate the inhibitory effects of NPY on the HPT axis.

Altered thyroid hormone levels affect body condition at metamorphosis in larvae of Xenopus laevis

2018 ◽  
Vol 38 (11) ◽  
pp. 1416-1425 ◽  
Author(s):  
Katharina Ruthsatz ◽  
Kathrin H. Dausmann ◽  
Claudia Drees ◽  
Laura I. Becker ◽  
Lisa Hartmann ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Xenopus Laevis ◽  
Body Condition ◽  
Hormone Levels ◽  
Thyroid Hormone Levels ◽  
Altered Thyroid

Plasma concentrations of cholecystokinin octapeptide and food intake in male rats treated with cholecystokinin octapeptide

1989 ◽  
Vol 121 (1) ◽  
pp. 59-65 ◽  
Author(s):  
A. Lindén ◽  
K. Uvnäs-Moberg ◽  
G. Forsberg ◽  
I. Bednar ◽  
P. Södersten
Keyword(s):  
Food Intake ◽  
Plasma Levels ◽  
Intraperitoneal Injection ◽  
Plasma Concentrations ◽  
Extended Period ◽  
Male Rats ◽  
Cholecystokinin Octapeptide ◽  
Cck Receptors ◽  
Cck Antagonist

ABSTRACT Intraperitoneal injection of 5 μg cholecystokinin octapeptide (CCK-8) into male rats deprived of food for 48 h produced a transient (less than 15 min) increase in plasma levels of CCK-8 but suppressed food intake for an extended period (45 min). Plasma concentrations of CCK-8 after i.p. injection of CCK-8 were raised to levels which were fairly comparable to those after feeding. Intracerebroventricular (i.c.v.) injection of the CCK antagonist proglumide (100 μg) reversed the effect of CCK-8 on food intake, while i.p. injection of proglumide (100 μg) did not have this effect. Feeding increased the plasma concentrations of somatostatin and gastrin but not of oxytocin, and somatostatin and oxytocin but not gastrin were released in response to i.p. injection of CCK-8. However, neither somatostatin nor oxytocin affected food intake, and their release in response to CCK-8 was unaffected by i.c.v. injection of proglumide. These results support the suggestion that CCK-8 is a physiological 'satiety' peptide, which can affect food intake in rats by mechanisms involving both peripheral and central CCK receptors. Journal of Endocrinology (1989) 121, 59–65

scholarly journals Warm Perches: A Novel Approach For Reducing Cold Stress Effect on Production, Plasma Hormones, and Immunity in Laying Hens

2021 ◽  
Author(s):  
Jiaying Hu ◽  
Heng Wei Cheng
Keyword(s):  
Body Weight ◽  
Cold Stress ◽  
Cold Exposure ◽  
Feed Intake ◽  
Plasma Levels ◽  
Egg Production ◽  
Laying Hens ◽  
Plasma Concentrations ◽  
Economic Losses ◽  
Stress Effect

Abstract Background: Cold temperature is a common environmental stressor that has a great impact on the poultry industries, inducing pathophysiological stress in birds with profound economic losses. Current methods used for preventing cold stress, such as reducing ventilation and using gas heaters, are facing challenges due to poor indoor air quality and its deleterious effects on bird and caretaker health. The aim of this study was to examine if the novelly designed warmed perch system, as a thermal device, can reduce cold stress-associated adverse effects on laying hens. Methods: Seventy-two 32-week-old DeKalb hens were randomly assigned to 36 cages arranged to 3 banks. The banks were assigned to 1 of 3 treatments: cages with warmed perches (WP; perches with circulating water at 30 oC), air perches (AP, regular perches only) or no perches (NP) for a 21- day trial. The room temperature was set at 10 oC during the entire experimental period. Rectal temperature and body weight were measured from the same bird of each cage at day 1, 8, 15, and 21 during the cold exposure. Egg production was recorded daily. Feed intake, egg and eggshell quality were determined during the 1st and 3rd week of cold stress. Plasma levels of corticosterone, thyroid hormones (3, 3’, 5-triiodothyronine and thyroxine), interleukin (IL)-6 and IL-10, were determined at day 1 and 21 post initiation of cold exposure. Results: Compared to both AP and NP hens, WP hens were able to maintain their body temperature without increasing feed intake and losing body weight. The eggs laid by WP hens had thicker eggshell during the 3rd week of cold exposure. Warmed perch hens also had a lower thyroxine conversion rate (3, 3’, 5-triiodothyronine/thyroxine) at day 1, while higher plasma concentrations of IL-6 at day 21. Plasma levels of corticosterone, 3, 3’, 5-triiodothyronine, and IL-10 were not different among treatments. Conclusions: Our results indicate that the warmed perch system can be used as a novel thermal device for preventing cold stress-induced negative effects on hen health and welfare through regulating innate immunity and metabolic hormonal homeostasis.

Altered thyroid hormone levels in bacterial sepsis: The role of nutritional adequacy

Metabolism ◽  
1980 ◽  
Vol 29 (10) ◽  
pp. 936-942 ◽  
Author(s):  
David A. Richmand ◽  
Mark E. Molitch ◽  
Thomas F. O'Donnell
Keyword(s):  
Thyroid Hormone ◽  
Bacterial Sepsis ◽  
Nutritional Adequacy ◽  
Hormone Levels ◽  
Thyroid Hormone Levels ◽  
Altered Thyroid
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