scholarly journals Effects of Maternal Levels of Thyroid Hormone (TH) on the Hypothalamus-Pituitary-Thyroid Set Point: Studies in TH Receptor β Knockout Mice

Endocrinology ◽  
2007 ◽  
Vol 148 (11) ◽  
pp. 5305-5312 ◽  
Author(s):  
Manuela Alonso ◽  
Charles Goodwin ◽  
XiaoHui Liao ◽  
David Page ◽  
Samuel Refetoff ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Elevated Serum ◽  
The Other ◽  
Long Term Effects ◽  
Intrauterine Environment ◽  
Set Point ◽  
Other Hand ◽  
Wild Type Phenotype ◽  
Pituitary Thyroid Axis ◽  
Serum Tsh

A level of thyroid hormone (TH) in agreement with the tissue requirements is essential for vertebrate embryogenesis and fetal maturation. In this study we evaluate the immediate and long-term effects of incongruent intrauterine TH levels between mother and fetus using the TH receptor (TR) β−/− knockout mouse as a model. We took advantage of the fact that the TRβ−/− females have elevated serum TH but are not thyrotoxic due to resistance to TH. We used crosses between heterozygotes with wild-type phenotype (TRβ+/−) males and TRβ−/− females, with a hyperiodothyroninemic (high T4 and T3 levels) intrauterine environment (TH congruent with the TRβ−/− fetus and excessive for the TRβ+/− fetus), and reciprocal crosses between TRβ−/− males and TRβ+/− females, providing a euiodothyroninemic intrauterine environment. We found that TRβ−/− dams had reduced litter sizes and pups with lower birth weight but preserved the mendelian TRβ−/− to TRβ+/− ratio at birth, indicating that the incongruous TH levels did not decrease intrauterine survival of a specific genotype. The results of studies in newborns demonstrate that TRβ+/− pups born to TRβ−/− dams have persistent suppression of serum TSH without a peak. On the other hand, TRβ−/− pups born to TRβ+/− dams have lower serum TSH at birth and a tendency to peak higher, compared with TRβ−/− pups born to TRβ−/− dams. The studies in the adult progeny demonstrate that TRβ+/− mice born to TRβ−/− dams and, thus, exposed to higher intrauterine TH levels, have greater resistance to TH at the level of the pituitary when stimulated with TRH. On the other hand, TRβ−/− mice born to TRβ+/− dams and, thus, deprived of TH in uterine life, were more sensitive to TH when similarly stimulated with TRH. Thus, TH exposure in utero has an effect on the regulatory set point of the hypothalamus-pituitary-thyroid axis, which can be seen early in life and persists into adulthood.

scholarly journals The Nuclear Receptor Corepressor (NCoR) Controls Thyroid Hormone Sensitivity and the Set Point of the Hypothalamic-Pituitary-Thyroid Axis

2011 ◽  
Vol 25 (2) ◽  
pp. 212-224 ◽  
Author(s):  
Inna Astapova ◽  
Kristen R. Vella ◽  
Preeti Ramadoss ◽  
Kaila A. Holtz ◽  
Benjamin A. Rodwin ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Nuclear Receptor ◽  
Hormone Sensitivity ◽  
Set Point ◽  
Nuclear Receptor Corepressor ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis

The effect of iodine deficiency and propylthiouracil on the hypothalamo–pituitary–thyroid axis in the neonatal rat

1978 ◽  
Vol 56 (6) ◽  
pp. 950-955 ◽  
Author(s):  
J. H. Dussault ◽  
P. Walker
Keyword(s):  
Tap Water ◽  
Elevated Serum ◽  
Thyroid Stimulating Hormone ◽  
Significant Decline ◽  
Neonatal Rat ◽  
Rapid Rise ◽  
Neonatal Rats ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
Serum Tsh

The effect of chronic propylthiouracil (PTU) and low iodide diet (LID) on the development of the hypothalamo–pituitary–thyroid axis in the rat has been studied. Pregnant and neonatal rats received 0.05% PTU in their drinking water or LID (distilled water and LID: Teklad Mills, Madison, Wisconsin). Control animals received tap water and Purina rat chow ad libitum. Hypothalamic thyrotropin-releasing hormone (TRH), pituitary and serum thyroid-stimulating hormone (THS), and serum thyroxine (T4) and triiodothyronine (T3) were measured by specific double-antibody radioimmunoassay. Both PTU- and LID-exposed animals had low hypothalamic TRH concentrations at 1 day and a rapid rise to peak levels of 2.4 ± 0.4 pg/μg protein (mean ± SEM) between 12 and 24 days in the PTU animals and 3.2 ± 0.4 pg/μg protein between 12 and 18 days in the LID rats. Hypothalamic TRH concentrations remained relatively stable in the PTU animals, whereas in the LID rats, after a brief but significant decline from 24 to 28 days, hypothalamic TRH concentrations rose to the highest values observed at 57 days (3.9 ± 0.5 pg/μg protein). Both groups of animals had elevated serum TSH levels at 1 day, with higher values seen in the PTU group (p < 0.01), and both showed a rapid rise at 12 days. Thereafter, serum TSH concentrations remained high in the PTU rats but declined to stable, albeit elevated, levels by 24 days (1260 ± 140 ng/ml) in the LID animals. Hypothyroidism was confirmed in the PTU animals by undetectable T4 and reduced T3 concentrations. In the LID rats, serum T4 concentrations rose from undetectable levels at 1 day to stable values by 32 days (2.18 ± 0.13 μg/dl). Serum T3 rose to peak values of 157.0 ± 6.9 ng/dl at 32 days and was elevated at all times after 12 days. These data suggest that chronic exposure to PTU or LID results in a marked derangement of the ontogenetic pattern of the hypothalamo–pituitary–thyroid axis. In addition, neonatal rats exposed to LID appear to respond appropriately by preferential T3 production.

PITUITARY-THYROID FUNCTION IN THYROTOXIC PATIENTS IN RELATION TO LONG-ACTING THYROID STIMULATOR (LATS) LEVELS

1970 ◽  
Vol 65 (4) ◽  
pp. 577-582 ◽  
Author(s):  
Minoru Fukuchi ◽  
Tohru Matsuoka ◽  
Tadashi Inoue ◽  
Kiyoshi Miyai ◽  
Yuichi Kumahara
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Function ◽  
Elevated Serum ◽  
Antithyroid Drug ◽  
Initial Values ◽  
Long Acting ◽  
Serum Tsh

ABSTRACT Serial changes in TSH, LATS, and thyroxine levels in the sera were studied following administration of an antithyroid drug or a thyroid hormone to thyrotoxic patients who became euthyroid after treatment. These changes were simultaneously determined by means of human TSH radioimmunoassay, McKenzie's bioassay. and the method of Murphy, respectively. Administration of 1-methyl-2-mercaptoimidazole (MMI) led to a decrease in thyroxine concentration and to a 6–10 times increase of the initial values in serum TSH concentration. Following administration of thyroxine at the end of the MMI treatment, the elevated serum TSH was rapidly decreased with an increase in thyroxine concentration. LATS activity, however, showed no significant changes throughout these experiments in which the reciprocal changes between TSH and thyroxine concentrations were observed.

THE EFFECT OF CODEINE ON RAT SERUM AMYLASE

1954 ◽  
Vol 32 (6) ◽  
pp. 625-627
Author(s):  
G. Stuart Wiberg ◽  
Jules Tuba
Keyword(s):  
Gall Bladder ◽  
Adult Male ◽  
Serum Amylase ◽  
Elevated Serum ◽  
Sphincter Of Oddi ◽  
The Other ◽  
Male Rats ◽  
Rat Serum ◽  
Other Hand

Adult male rats did not display an elevated serum amylase following injection of codeine. Mice, on the other hand, showed significantly increased values of the enzyme after treatment with codeine. The significance of these findings are discussed from the standpoint of the tonus of the sphincter of Oddi, and the presence or absence of a gall bladder.

Familial Partial Peripheral and Pituitary Resistance to Thyroid Hormone: A Frequently Missed Diagnosis?

PEDIATRICS ◽  
1986 ◽  
Vol 78 (6) ◽  
pp. 1114-1122
Author(s):  
Nancy J. Hopwood ◽  
Sue Ellyn Sauder ◽  
Brahm Shapiro ◽  
James C. Sisson
Keyword(s):  
Thyroid Hormone ◽  
Family Members ◽  
Elevated Serum ◽  
Thyroid Stimulating Hormone ◽  
Thyrotropin Releasing Hormone ◽  
Resistance To Thyroid Hormone ◽  
Releasing Hormone ◽  
Thyroxine Therapy ◽  
Missed Diagnosis ◽  
Serum Tsh

The diagnosis of partial peripheral and pituitary resistance to thyroid hormone was ultimately made in two boys, 7 and 9 years of age, and a 10-year-old girl who had goiters and hyperthyroxinemia. The boys were treated with propythiouracil and/or thyroidectomy or iodine 131 for suspected thyrotoxicosis but had poorly suppressible serum thyroid-stimulating hormone (TSH) post treatment in spite of the usual L-thyroxine replacement. The girl had increasing goiter size while receiving propylthiouracil, 100 mg every eight hours. These findings led to reevaluation of thyroid hormone dynamics in these children and their families. Twelve additional family members, 3 to 38 years of age, compatible with an autosomal dominant inheritance, were also found to have peripheral and pituitary resistance to thyroid hormone. All affected individuals had elevated serum thyroxine and triiodothyronine levels, normal to slightly elevated triiodothyronine resin uptakes, and a nonsuppressed serum TSH. The five individuals who were given thyrotropin-releasing hormone showed exaggerated TSH responses, which normalized on L-thyroxine therapy. Misdiagnosis in six of 15 family members led to significant morbidity (hypothyroidism, delayed growth, and therapy risk). A nonsuppressed serum TSH in a patient with suspected thyrotoxicosis should lead to suspicion of this disorder. Appropriate management for this condition includes L-thyroxine therapy to decrease goiter size and normalize TSH responses to thyrotropin-releasing hormone.

scholarly journals An unusual complementation in non-excitable mutants in Paramecium

2000 ◽  
Vol 76 (2) ◽  
pp. 125-133 ◽  
Author(s):  
ATSUSHI MATSUDA ◽  
YOSHIRO SAIMI ◽  
MIHOKO TAKAHASHI
Keyword(s):  
Genetic Relationship ◽  
The Other ◽  
Unusual Feature ◽  
Marker Genes ◽  
Paramecium Tetraurelia ◽  
Wild Type ◽  
Other Hand ◽  
Wild Type Phenotype ◽  
Allelic Interaction

A non-excitable behavioural mutant, d4-662, was previously characterized as the fourth pawn locus mutant pwD in Paramecium tetraurelia. We now provide data demonstrating that d4-662 is in fact controlled by a pwB allele that has the unusual feature of complementing other pwB alleles in heterozygous F1 progeny. Neither the cytoplasm nor the nucleoplasm of d4-662 cured the mutational defects of pwB and in the reverse combination of d4-662 and pwB, the result was the same. On the other hand, pwA, another non-excitable mutant, was cured upon cross-injection with d4-662 and mutants carrying trichocyst non-discharge marker genes were also cured. This evidence suggests that d4-662 is a new mutant belonging to pwB, and would be better designated as pwB662. Extensive crossbreeding analyses, however, showed an unusual genetic relationship between d4-662 and pwB (pwB95 or pwB96). When d4-662 was crossed with pwB mutants, many progeny expressing wild-type phenotype or mixed clones of wild-type and pawn cells were obtained in the F1. Less than 12·5% expressed the pawn phenotype. The appearance of wild-type progeny in this F1 strongly suggests that an inter-allelic interaction between pwB662 and other pwB alleles may occur during development of the macronucleus.

scholarly journals Long term effects of formaldehyde preservation on subsequent bone maceration procedures: a comparative study between cold and hot water maceration

1970 ◽  
Vol 6 (2) ◽  
pp. 1000-1008
Author(s):  
Ayodeji S.O. Odukoya ◽  
Oluwaseun Ajani ◽  
Taiye S. Adelodun
Keyword(s):  
Comparative Study ◽  
Cold Water ◽  
The Body ◽  
Hot Water ◽  
The Other ◽  
Water Bodies ◽  
Long Term Effects ◽  
Other Hand ◽  
Small Bones

This study was conducted to compare the effectiveness of cold and hot water maceration techniques for the development of bone specimens from cadavers. Three already dissected bodies of both sexes (two males and a female) obtained from the Department of Anatomy, Bowen University, Iwo, Osun State, Nigeria were used. The male bodies were labelled as A and B and the female as C. Before maceration, the heights of the bodies were taken to be 165 cm, 170 cm and 160 cm for A, B and C respectively. The bodies were preserved in formalin for 4 years before being used. Hot water maceration involves cooking bones in water. Bodies A and C were used in this method. While cold water maceration is simply by soaking the body in water until all the remaining flesh was removed. Hot water maceration showed changes in color of the bones, shrinkage of the bones, oily substances were seen on the surface of the chloroform during degreasing and the bones were very soft after bleaching but got harder after drying with sunlight. Cold water maceration on the other hand kept the bones white and maintained their integrity though it required a lot of time. Small bones had their flesh removed quickly in few weeks, while larger and longer bones took months. We conclude that cold water maceration done properly, results in cleaner bones and better morphological outcomes than hot water method though it requires much time.KEYWORDS: Maceration, Formaldehyde, Comparative, Bones, Hot water, Cold water

scholarly journals Disfunción tiroidea posexposición a medio de contraste yodado

2017 ◽  
Vol 2 (1) ◽  
pp. 5-9
Author(s):  
Cristian Iván García Rincón ◽  
Luz Yaneth Becerra Salazar ◽  
Germán Alberto Moreno Gómez ◽  
Henry Mauricio Arenas Quintero
Keyword(s):  
Coronary Artery Disease ◽  
Coronary Artery ◽  
Thyroid Hormone ◽  
Iodine Concentration ◽  
The Other ◽  
Thyroid Peroxidase ◽  
High Iodine ◽  
Other Hand ◽  
All Cause Mortality ◽  
Artery Disease

La exposición a cantidades excesivas de yodo bloquea la actividad de la enzima peroxidasa tiroidea (TPO), un fenómeno conocido como efecto de Wolff-Chaikoff. Clínicamente, éste puede llevar a hipotiroidismo. Por el contrario, cuando un tirocito contiene valores bajos de yodo y es expuesto a elevadas concentraciones del mismo, aumenta de forma significativa la producción de hormona tiroidea, llevando frecuentemente a hipertiroidismo clínico y bioquímico, fenómeno conocido como efecto de Jod-Basedow. Tanto el hiper como el hipotiroidismo aumentan el riesgo de enfermedad arterial coronaria, miopatía ventricular izquierda, anormalidades electrofisiológicas, además de incrementar la mortalidad cardiovascular y por todas las causas.Abstract Exposure to excessive amounts of iodine blocks the activity of the enzyme thyroid peroxidase (TPO), a phenomenon known as Wolf-Chaikoff effect. Clinically, this effect can lead to hypothyroidism. On the other hand, when thyrocites have low iodine levels and are exposed to a high iodine concentration, they increase significantly their production of thyroid hormone thus leading to hyperthyroidism, a phenomenon known as Jod-Basedow effect. Both hypothyroidism and hyperthyroidism increase the risk of coronary artery disease, left cardiomyopathy, electrophysiological abnormalities, and all-cause mortality.

THE EFFECT OF CODEINE ON RAT SERUM AMYLASE

1954 ◽  
Vol 32 (1) ◽  
pp. 625-627 ◽  
Author(s):  
G. Stuart Wiberg ◽  
Jules Tuba
Keyword(s):  
Gall Bladder ◽  
Adult Male ◽  
Serum Amylase ◽  
Elevated Serum ◽  
Sphincter Of Oddi ◽  
The Other ◽  
Male Rats ◽  
Rat Serum ◽  
Other Hand

Adult male rats did not display an elevated serum amylase following injection of codeine. Mice, on the other hand, showed significantly increased values of the enzyme after treatment with codeine. The significance of these findings are discussed from the standpoint of the tonus of the sphincter of Oddi, and the presence or absence of a gall bladder.

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