scholarly journals Thyroid hormone modulation during zebrafish development recapitulates evolved diversity in danionin jaw protrusion mechanics

2018 ◽  
Author(s):  
Demi Galindo ◽  
Elly Sweet ◽  
Zoey DeLeon ◽  
Mitchel Wagner ◽  
Adrian DeLeon ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Developmental Stages ◽  
Fish Larvae ◽  
High Water ◽  
Shape Variation ◽  
Adult Zebrafish ◽  
Hormone Production ◽  
Evolutionary Diversification ◽  
Feeding Mechanics ◽  
Jaw Protrusion

AbstractOne of three vertebrates belongs to a fish lineage for which protrusile jaws are a synapomorphy. Identifying the developmental determinants of protrusion ability will improve our understanding of an important area of evolutionary diversification. The high water viscosities experienced by tiny fish larvae inhibit the viability of protrusile jaws. In the zebrafish protrusion does not arise until after metamorphosis. Fish metamorphosis typically includes significant changes in trophic morphology, accompanies a shift in feeding niche and coincides with increased thyroid hormone production. We tested whether thyroid hormone affects the development of zebrafish feeding mechanics. We found that it affected all developmental stages examined, but that these effects were most pronounced after metamorphosis. Thyroid hormone levels affected the development of jaw morphology, feeding mechanics, shape variation and cranial ossification. Adult zebrafish utilize protrusile jaws, but an absence of thyroid hormone eliminated postmetamorphic remodeling of the premaxilla and the premaxillary structure that permits protrusion never formed. The premaxillae of late juvenile and adult zebrafish are similar to those found in the adults of other Danio species. Premaxillae from early juvenile zebrafish and hypothyroid adult zebrafish resemble those from adults in the genera Danionella, Devario and Microdevario that show little to no jaw protrusion.

scholarly journals Capture efficiency for small dominant mesozooplankters (Copepoda, Appendicularia) off Buenos Aires Province (34ºS-41ºS), Argentine Sea, using two plankton mesh sizes

2009 ◽  
Vol 57 (3) ◽  
pp. 205-214 ◽  
Author(s):  
Rosana Di Mauro ◽  
Fabiana Capitanio ◽  
María Delia Viñas
Keyword(s):  
Buenos Aires ◽  
Developmental Stages ◽  
Fish Larvae ◽  
Abundant Species ◽  
Accurate Estimation ◽  
Buenos Aires Province ◽  
Oikopleura Dioica ◽  
Great Loss ◽  
Argentine Sea ◽  
Significant Difference

Two plankton mesh sizes of 67 µm and 220 µm were compared to evaluate their efficiency in the capture of the smallest copepods and appendicularians present in the Buenos Aires coastal area (Argentine Sea). A total of 12 copepod species and one appendicularian species were recorded in this study. The copepods were separated into 4 groups: harpacticoids, cyclopoids, small calanoids and large calanoids and their developmental stages. Among the cyclopoids, Oithona nana was the most abundant species, being 96.29 % underestimated by the 220 µm mesh, whereas Microsetella norvegica dominated the harpacticoids and was captured exclusively by the smaller mesh. Similar results were found for copepodites I-III of small calanoids, whose net sampled underestimation reached 99.70%. On the other hand, no significant difference between meshes was found for adults and copepodites IV-V of small calanoids or any of the developmental stages of large calanoids. A great loss of biomass was observed for O. nana when applying the larger mesh. In regards to the appendicularian Oikopleura dioica, all size ranges below 1,000 µm length were better estimated by the 67 µm mesh in terms of abundance and biomass. Our results clearly show that the 67 µm mesh was more efficient in the capture of early stages of small copepods thus providing a more accurate estimation of the fish larvae prey field.

scholarly journals Thyroid hormones and fetal neurological development

2011 ◽  
Vol 209 (1) ◽  
pp. 1-8 ◽  
Author(s):  
J Patel ◽  
K Landers ◽  
H Li ◽  
R H Mortimer ◽  
K Richard
Keyword(s):  
Thyroid Hormone ◽  
Cell Membrane ◽  
Hormone Receptors ◽  
Developmental Stages ◽  
Fetal Brain ◽  
Neurological Development ◽  
Thyroid Hormone Metabolism ◽  
Pituitary Thyroid Axis ◽  
Fetal Thyroid ◽  
Type 3

The development of fetal thyroid function is dependent on the embryogenesis, differentiation, and maturation of the thyroid gland. This is coupled with evolution of the hypothalamic–pituitary–thyroid axis and thyroid hormone metabolism, resulting in the regulation of thyroid hormone action, production, and secretion. Throughout gestation there is a steady supply of maternal thyroxine (T4) which has been observed in embryonic circulation as early as 4 weeks post-implantation. This is essential for normal early fetal neurogenesis. Triiodothyronine concentrations remain very low during gestation due to metabolism via placental and fetal deiodinase type 3. T4 concentrations are highly regulated to maintain low concentrations, essential for protecting the fetus and reaching key neurological sites such as the cerebral cortex at specific developmental stages. There are many known cell membrane thyroid hormone transporters in fetal brain that play an essential role in regulating thyroid hormone concentrations in key structures. They also provide the route for intracellular thyroid hormone interaction with associated thyroid hormone receptors, which activate their action. There is a growing body of experimental evidence from rats and humans to suggest that even mild maternal hypothyroxinemia may lead to abnormalities in fetal neurological development. Our review will focus on the ontogeny of thyroid hormone in fetal development, with a focus on cell membrane transporters and TR action in the brain.

Thyrotrophin-producing pituitary adenomas

1982 ◽  
Vol 57 (4) ◽  
pp. 515-519 ◽  
Author(s):  
Stephen A. Hill ◽  
James M. Falko ◽  
Charles B. Wilson ◽  
William E. Hunt
Keyword(s):  
Thyroid Hormone ◽  
Pituitary Adenomas ◽  
Preoperative Diagnosis ◽  
Pituitary Tumors ◽  
Recurrent Tumor ◽  
Hormone Production ◽  
Content Type ◽  
Aggressive Tumor ◽  
Tsh Levels ◽  
Fine Print

✓ Hyperthyroidism due to thyrotrophin (TSH)-secreting pituitary tumors is rare. Four cases are described, with the features that allow preoperative diagnosis. In all the patients, thyroid hormone production was consistently elevated despite antithyroid therapy, and TSH levels were inappropriately elevated. All patients were treated with both surgery and irradiation. Each patient had recurrent tumor with suprasellar, intrasphenoidal, or intraorbital spread. The combination of a recurrent, aggressive tumor complicated by thyrotoxicosis makes this a complex and difficult surgical problem.

Factors Affecting Glucocorticoid and Thyroid Hormone Production of Island Foxes

2019 ◽  
Vol 84 (3) ◽  
pp. 505-514
Author(s):  
Corinne P. Kozlowski ◽  
Helen Clawitter ◽  
Angela Guglielmino ◽  
Juliann Schamel ◽  
Stacy Baker ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Hormone Production ◽  
Factors Affecting

In vivo effects of flavonoid EMD 21388 on thyroid hormone secretion and metabolism in rats

1991 ◽  
Vol 261 (2) ◽  
pp. E227-E232 ◽  
Author(s):  
J. P. Schroder-van der Elst ◽  
D. van der Heide ◽  
J. Kohrle
Keyword(s):  
Thyroid Hormone ◽  
Hormone Secretion ◽  
Male Rats ◽  
Intact Male ◽  
Hormone Production ◽  
Iodide Uptake ◽  
Brown Adipose ◽  
In Vivo Effects

In vitro, the synthetic flavonoid EMD 21388 appears to be a potent inhibitor of thyroxine (T4) 5'-deiodinase and diminishes binding of T4 to transthyretin. In this study, in vivo effects of long-term administration of EMD 21388 on thyroid hormone production and metabolism were investigated. Intact male rats received EMD 21388 (20 mumol.kg body wt-1.rat-1.day-1) for 14 days. [125I]T4 and 3,5,3'-[131I]triiodotyronine (T3) were infused continuously and intravenously in a double-isotope protocol for the last 10 and 7 days, respectively. EMD 21388 decreased plasma thyroid hormone concentrations, but thyrotropin levels in plasma and pituitary did not change. Plasma clearance rates for T4 and T3 increased. Thyroidal T4 secretion was diminished, but T3 secretion was elevated. Extrathyroidal T3 production by 5'-deiodination was lower. T4 concentrations were markedly lower in all tissues investigated. Total tissue T3 was lower in brown adipose tissue, brain, cerebellum, and pituitary, tissues that express the type II 5'-deiodinase isozyme due to decreased local T3 production. Most tissues showed increased tissue/plasma ratios for T4 and T3. These results indicate that this flavonoid diminished T4 and increased T3 secretion by the thyroid, probably in analogy with other natural flavonoids, by interference with one or several steps between iodide uptake, organification, and hormone synthesis.

Effects of marginal iodine deficiency during pregnancy: iodide uptake by the maternal and fetal thyroid

1997 ◽  
Vol 273 (6) ◽  
pp. E1121-E1126 ◽  
Author(s):  
P. M. Versloot ◽  
J. P. Schröder-Van Der Elst ◽  
D. Van Der Heide ◽  
L. Boogerd
Keyword(s):  
Thyroid Hormone ◽  
Iodine Deficiency ◽  
Specific Activity ◽  
Hormone Production ◽  
Iodide Uptake ◽  
Deficient Diet ◽  
Pregnant Rats ◽  
Thyroid Hormone Metabolism ◽  
Fetal Thyroid ◽  
The Absolute

Iodide uptake by the thyroid is an active process. Iodine deficiency and pregnancy are known to influence thyroid hormone metabolism. The aim of this study was to clarify the effects of iodine deficiency and pregnancy on iodide uptake by the thyroid. Radioiodide was injected intravenously into nonpregnant and 19-day pregnant rats receiving a normal or marginally iodine-deficient diet. The uptake of radioiodide by the thyroid was measured continuously for 4 h. The absolute iodide uptake by the maternal and fetal thyroid glands at 24 h was calculated by means of the urinary specific activity. Pregnancy resulted in a decrease in the absolute thyroidal iodide uptake. Marginal iodine deficiency had no effect on the absolute iodide uptake by the maternal thyroid. The decreased plasma inorganic iodide was compensated by an increase in thyroidal clearance. A similar compensation was not found for the fetus; the uptake of iodide by the fetal thyroid decreased by 50% during marginal iodine deficiency. This can lead to diminished thyroid hormone production, which will have a negative effect on fetal development, especially of the brain.

scholarly journals Experimental copper exposure, but not heat stress, leads to elevated intraovarian thyroid hormone levels in three-spined sticklebacks (Gasterosteus aculeatus)

Ecotoxicology ◽  
2020 ◽  
Vol 29 (9) ◽  
pp. 1431-1440
Author(s):  
Ruuskanen Suvi ◽  
Mottola Giovanna ◽  
Anttila Katja
Keyword(s):  
Heat Stress ◽  
Thyroid Hormone ◽  
Nuclear Power ◽  
Power Plants ◽  
Gasterosteus Aculeatus ◽  
High Water ◽  
Population Variation ◽  
Copper Exposure ◽  
Fish Model ◽  
Maternal Hormones

Abstract Climate change and pollution are some of the greatest anthropogenic threats to wild animals. Transgenerational plasticity—when parental exposure to environmental stress leads to changes in offspring phenotype—has been highlighted as a potential mechanism to respond to various environmental and anthropogenic changes across taxa. Transgenerational effects may be mediated via multiple mechanisms, such as transfer of maternal hormones to eggs/foetus. However, sources of variation in hormone transfer are poorly understood in fish, and thus the first step is to characterise whether environmental challenges alter transfer of maternal hormones to eggs. To this end, we explored the population variation and environmental variation (in response to temperature and endocrine disrupting copper) in maternal thyroid hormone (TH), transfer to offspring in a common fish model species, the three-spined stickleback (Gasterosteus aculeatus) using multiple approaches: (i) We compared ovarian TH levels among six populations across a wide geographical range in the Baltic Sea, including two populations at high water temperature areas (discharge water areas of nuclear power plants) and we experimentally exposed fish to (ii) environmentally relevant heat stress and (iii) copper for 7 days. We found that populations did not differ in intraovarian TH levels, and short-term heat stress did not influence intraovarian TH levels. However, copper exposure increased both T4 and T3 levels in ovaries. The next step would be to evaluate if such alterations would lead to changes in offspring phenotype.

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