The effects of insulin on TSH secretion and the morphology and physiology of the thyroid in the lizard Podarcis s. sicula

1996 ◽  
Vol 17 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Anna Capaldo ◽  
Vincenza Laforgia ◽  
Rosaria Sciarrillo ◽  
Antimo Cavagnuolo
Keyword(s):  
Thyroid Gland ◽  
Thyroid Hormones ◽  
Plasma Concentrations ◽  
Thyroid Stimulating Hormone ◽  
Lizard Species ◽  
Podarcis Sicula ◽  
Tsh Secretion ◽  
Stimulating Hormone

AbstractInsulin was administered to Podarcis sicula in winter, when the thyroid gland is inhibited. The activity of the thyroid increased, plasma concentrations of thyroid hormones and hepatic 5'-monodeiodinase activity (MDA) increased, and thyroid stimulating hormone (TSH) concentrations fell to undetectable values. This result confirms the influence of insulin on the activity of the thyroid gland in the lizard species studied. The mechanisms are still unclear, although there is evidence which leads us to believe that insulin is directly responsible for thyroid activation.

HYPOTHALAMIC SECRETION OF THYROTROPHIN RELEASING HORMONE IS DECREASED IN MALE JAPANESE QUAIL EXPOSED TO LONG DAILY PHOTOPERIODS

1982 ◽  
Vol 92 (2) ◽  
pp. 261-265 ◽  
Author(s):  
O. F. X. ALMEIDA
Keyword(s):  
Thyroid Gland ◽  
Japanese Quail ◽  
Adult Male ◽  
Plasma Concentrations ◽  
Thyroid Stimulating Hormone ◽  
Blood Concentrations ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Stimulating Hormone

Adult male Japanese quail held under short daily photoperiods (8 h light: 16 h darkness; 8L : 16D) had significantly higher plasma concentrations of thyroid-stimulating hormone (TSH), tri-iodothyronine (T3) and thyroxine (T4) than did those kept under long days (16L : 8D). When given a single s.c. injection of 50 μg thyrotrophin releasing hormone (TRH) the birds held under both the 8L : 16D and 16L : 8D photoperiods showed rapid increases in their blood concentrations of TSH, T4 and T3, the amplitude of the TSH response of the birds exposed to 16L : 8D being particularly marked. These results suggest that, in the male quail, long daily photoperiods produce a hypothyroid state as a result of diminished TRH secretion. The synthetic and secretory capacities of the thyroid gland and pituitary thyrotrophs are apparently unimpaired by long days.

Establishment of Early Pregnancy Related Thyroid Hormone Models and Reference Intervals for Pregnant Women in China Based on Real World Data

2021 ◽  
Vol 53 (04) ◽  
pp. 272-279
Author(s):  
Chaochao Ma ◽  
Xiaoqi Li ◽  
Lixin Liu ◽  
Xinqi Cheng ◽  
Fang Xue ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Pregnant Women ◽  
Early Pregnancy ◽  
Gestational Age ◽  
Dynamic Change ◽  
Reference Intervals ◽  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
Stimulating Hormone

AbstractThyroid hormone reference intervals are crucial for diagnosing and monitoring thyroid dysfunction during early pregnancy, and the dynamic change trend of thyroid hormones during pregnancy can assist clinicians to assess the thyroid function of pregnant women. This study aims to establish early pregnancy related thyroid hormones models and reference intervals for pregnant women. We established two derived databases: derived database* and derived database#. Reference individuals in database* were used to establish gestational age-specific reference intervals for thyroid hormones and early pregnancy related thyroid hormones models for pregnant women. Individuals in database# were apparently healthy non-pregnant women. The thyroid hormones levels of individuals in database# were compared with that of individuals in database* using nonparametric methods and the comparative confidence interval method. The differences in thyroid stimulating hormone and free thyroxine between early pregnant and non-pregnant women were statistically significant (p<0.0001). The reference intervals of thyroid stimulating hormone, free thyroxine and free triiodothyronine for early pregnant women were 0.052–3.393 μIU/ml, 1.01–1.54 ng/dl, and 2.51–3.66 pg/ml, respectively. Results concerning thyroid stimulating hormone and free thyroxine reference intervals of early pregnancy are comparable with those from other studies using the same detection platform. Early pregnancy related thyroid hormones models showed various change patterns with gestational age for thyroid hormones. Early pregnancy related thyroid hormones models and reference intervals for pregnant women were established, so as to provide accurate and reliable reference basis for the diagnosing and monitoring of maternal thyroid disfunction in early pregnancy.

Iodide Metabolism and Effects

2020 ◽  
pp. 25-33
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Gland ◽  
Thyroid Hormones ◽  
Dietary Supplement ◽  
Thyroid Function ◽  
Thyroid Stimulating Hormone ◽  
Hormone Synthesis ◽  
Serum Tsh ◽  
Tsh Stimulation ◽  
Sensitive Marker

Iodine (I2) is essential in the synthesis of thyroid hormones T4 and T3 and functioning of the thyroid gland. Both T3 and T4 are metabolically active, but T3 is four times more potent than T4. Our body contains 20-30 mg of I2, which is mainly stored in the thyroid gland. Iodine is naturally present in some foods, added to others, and available as a dietary supplement. Serum thyroid stimulating hormone (TSH) level is a sensitive marker of thyroid function. Serum TSH is increased in hypothyroidism as in Hashimoto's thyroiditis. In addition to regulation of thyroid function, TSH promotes thyroid growth. If thyroid hormone synthesis is chronically impaired, TSH stimulation eventually may lead to the development of a goiter. This chapter explores the iodide metabolism and effects of Hashimoto's disease.

The Thyroid Gland: Physiology and Pathophysiology

2000 ◽  
Vol 19 (8) ◽  
pp. 11-26 ◽  
Author(s):  
Denise Kirsten
Keyword(s):  
Thyroid Gland ◽  
Thyroid Hormones ◽  
Laboratory Tests ◽  
Clinical Manifestations ◽  
Thyroid Stimulating Hormone ◽  
The Body ◽  
Premature Delivery ◽  
Follicular Cells ◽  
Metabolic Hormones ◽  
Radiologic Findings

The thyroid gland contains many follicular cells that store the thyroid hormones within the thyroglobulin molecule until they are needed by the body. The thyroid hormones, often referred to as the major metabolic hormones, affect virtually every cell in the body. Synthesis and secretion of the thyroid hormones depend on the presence of iodine and tyrosine as well as maturation of the hypothalamic-pituitary-thyroid system. Interruption of this development, as occurs with premature delivery, results in inadequate production of thyroid-stimulating hormone and thyroxine, leading to a variety of physiologic conditions. Pathologic conditions occur in the presence of insufficient thyroid production or a defect in the thyroid gland. Laboratory tests are important in diagnosing conditions of the thyroid gland. A thorough history in combination with clinical manifestations and radiologic findings are also useful in diagnosing specific thyroid conditions. Nurses play an important role in identifying and managing thyroid disorders and in providing supportive care to infants and their families.

A role for thyroid hormones in cold-induced elevation of blood pressure and cardiac hypertrophy

1994 ◽  
Vol 72 (9) ◽  
pp. 1066-1074 ◽  
Author(s):  
Melvin J. Fregly ◽  
Fabian Rossi ◽  
J. Robert Cade
Keyword(s):  
Blood Pressure ◽  
Cardiac Hypertrophy ◽  
Thyroid Hormones ◽  
Antithyroid Drug ◽  
Thyroid Stimulating Hormone ◽  
Control Group ◽  
Acute Administration ◽  
Induced Hypertension ◽  
Blood Pressures ◽  
Stimulating Hormone

The systolic blood pressures of two groups of rats that were exposed to cold (5 °C) for 4 weeks were elevated significantly above that of warm-acclimated controls maintained at 24 °C. At this time these groups were given the antithyroid drug aminotriazole in their food at 0.3 g/kg. At the same time, one group was given 15.8 μg thyroxine (T4)/kg body mass per day, while the second received 31.6. The doses were chosen as replacement (15.8 μg/kg) and twice replacement (31.8 μg/kg) for the rats. The results of the study revealed that both groups receiving aminotriazole and T4 had reductions in blood pressure within 1 week of initiation of treatment. Blood pressures reached control level after 5 weeks. Cardiac hypertrophy accompanying cold-induced hypertension was reduced with the lower dose of T4 and prevented with the higher dose. Serum concentrations of T4 and triiodothyronine (T3) in the two treated groups were reduced, while serum thyroid-stimulating hormone concentration and thyroid mass were increased above that of the warm-acclimated control group. This suggests that the rats were hypothyroid relative to the warm-acclimated control group. However, the treated rats grew at the same rate as nontreated, cold-exposed controls and had similar food and water intakes, a similar dipsogenic response to acute administration of isoproterenol, and similar colonic temperatures. These measurements suggest that the rats were not functionally hypothyroid. Nevertheless, the results suggest that a paradigm in which the secretory ability of the thyroid gland is blocked, and T4 is returned at a constant, albeit suboptimal, level, reduced blood pressure and cardiac hypertrophy in cold-exposed rats. Hence, the increased turnover of thyroid hormones that characteristically accompanies exposure to cold plays a role in these changes. These studies also indicate that an increase in the rate of secretion of T4 is not required for survival in cold air.Key words: cold-induced hypertension, thyroxine, triiodothyronine, thyroid-stimulating hormone, aminotriazole, antithyroid drug, blood pressure, cardiac hypertrophy, catecholamines, norepinephrine, epinephrine, dopamine.

Interaction of adrenals and thyroid in maintenance of body temperature of rats exposed to cold

1960 ◽  
Vol 199 (3) ◽  
pp. 437-444 ◽  
Author(s):  
Melvin J. Fregly
Keyword(s):  
Body Temperature ◽  
Thyroid Gland ◽  
Cooling Rate ◽  
Thyroid Stimulating Hormone ◽  
Cortisone Acetate ◽  
Simultaneous Administration ◽  
Naturally Occurring ◽  
Effective Administration ◽  
Adrenalectomized Rats ◽  
Stimulating Hormone

The effects of cortisone acetate and thyroxine, administered separately or in combination, on colonic cooling rate (CCR) have been studied in restrained, adrenalectomized rats subjected to air at 5°C. Thyroxine alone at 5.0 µg/day reduced the rapid CCR of adrenalectomized rats but failed to return it to that of sham-operated rats. Cortisone acetate alone at 1.0 mg/day reduced CCR but also failed to restore it to normal. A higher dose (2.0 mg/day) was even less effective. Administration of 5.0 µg/day thyroxine simultaneously with 2.0–2.5 mg cortisone acetate returned CCR to that of sham-operated rats. Simultaneous administration of cortisone acetate with graded doses of thyroid stimulating hormone (TSH) to adrenalectomized rats resulted in greater reduction of CCR than with either treatment alone. Cortisone acetate did not appear to interfere either with tissue utilization of thyroxine or with thyroid gland response to TSH administration. The cooling test has also proved a useful tool for comparing potencies of a synthetic (dexamethasone) and a naturally occurring steroid (progesterone) with that of cortisone acetate. Dexamethasone is estimated to have a potency 700 times that of cortisone acetate, while progesterone is only one-third as potent.

THE DEVELOPMENT OF THYROID-STIMULATING HORMONE-RELEASING FACTOR ACTIVITY IN THE NEONATAL RABBIT

1971 ◽  
Vol 49 (4) ◽  
pp. 559-567 ◽  
Author(s):  
A. ŚLEBODZIŃSKI ◽  
Z. MACH ◽  
W. MALINOWSKA
Keyword(s):  
Thyroid Gland ◽  
Thyroid Stimulating Hormone ◽  
Chick Embryos ◽  
Factor Activity ◽  
Embryo Chick ◽  
Stimulating Hormone

SUMMARY Nine-day chick embryos received grafts of hypothalamus, adenohypophysis, thyroid, and fat (controls) from 0-, 7-, 14- and 21-day-old rabbits to the chorio-allantois. In addition, aqueous rabbit adenohypophysial and hypothalamic extracts were given to 1-day-old chicks. Animals injected with thyrotrophin and saline served as controls. On the 5th day of incubation of treated embryos, or 24 h after the administration of the extracts, the chicks were killed and their thyroids studied histologically. The hypothalamic grafts or extracts activated the chick thyroid gland and a similar trend was found in adenohypophysial or thyroid-stimulating hormone-treated chicks. The degree of activation of the embryo chick thyroid gland was related to the age of the donor rabbit. In general, thyroidstimulating hormone-releasing factor activity in hypothalamic heterografts or extracts appeared first in 14-day-old rabbits and was correlated with increasing thyrotrophic potency of the rabbit adenohypophysis.

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