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Full-Text Articles in Endocrinology

Apobec3 Regulation By Thyroid Hormone, Michelle Santiago Jan 2023

Apobec3 Regulation By Thyroid Hormone, Michelle Santiago

All Graduate Theses, Dissertations, and Other Capstone Projects

Thyroid hormone (TH) is crucial for many biological processes, including the development of the auditory system. Appropriate thyroid hormone signaling is important for the development of the cochlea, leading to the successful onset of hearing. More specifically, TH influences the timing of remodeling of the greater epithelial ridge (GER), a transient cochlear structure that secretes proteins that contribute to the formation of the tectorial membrane. Developmental hypothyroidism results in delayed GER regression, whereas excess TH results in premature remodeling. Both conditions result in deafness. However, it is unknown how TH mediates GER remodeling. Expression profiling identified APOBEC3 (A3) as a …


Characterization Of Deiodinase Expression In The Hypothyroid Developing Cochlea, Maria A. Uscategui Calderon Jan 2020

Characterization Of Deiodinase Expression In The Hypothyroid Developing Cochlea, Maria A. Uscategui Calderon

All Graduate Theses, Dissertations, and Other Capstone Projects

Thyroid hormone (TH) is essential for cochlear development and normal auditory function. Considering the importance of TH in mediating cochlear development, understanding the degree to which developing tissues can adapt to perturbations in thyroid hormone signaling is extremely important. The deiodinases (D2 and D3) are enzymes that tightly control TH availability at the tissue level and have been proposed to function as adaptive mechanisms that maintain tissue TH homeostasis. D2 converts thyroxine (T4) to a biologically active ligand triiodothyronine (T3); locally amplifying a T3 signal. Conversely, Dio3 inactivates T3 and T4 by converting these iodothyronines to the inactive metabolites diiodothyronine …


The Relationship Between Seasonal Breeding And Deiodinase Expression In The Green Anole Lizard, Hyejoo Kang Jan 2019

The Relationship Between Seasonal Breeding And Deiodinase Expression In The Green Anole Lizard, Hyejoo Kang

All Graduate Theses, Dissertations, and Other Capstone Projects

Reproductive physiology and behavior is mainly regulated by the hypothalamus-pituitary-gonad (HPG) axis. Interestingly, abnormal levels of thyroid hormone (TH) results in the delayed onset of puberty and affects gonadal function of adults by altering HPG axis activity. Seasonally breeding animals undergo drastic hormonal and behavioral changes between breeding and non-breeding seasons. Green anole lizards (Anolis carolinensis), similar to other seasonally breeding animals, have increased sex steroid hormones, larger gonads, upregulated gonadal steroidogenic acute regulatory protein (StAR) mRNA and increased reproductive behavior during the breeding compared to non-breeding seasons. Relatively less is known regarding the regulation of gonadal TH in seasonal …


Quantification Of Brain-Region Specific Alterations In Insulin-Like Growth Factor-1 Expression During Developmental Hypothyroidism, Cari Lee Graber-Feesl Jan 2017

Quantification Of Brain-Region Specific Alterations In Insulin-Like Growth Factor-1 Expression During Developmental Hypothyroidism, Cari Lee Graber-Feesl

All Graduate Theses, Dissertations, and Other Capstone Projects

Insufficient thyroid hormone (TH) during development results in permanent neurological deficits. These deficits are the result of perturbed TH-mediated brain development. Interestingly, insufficient insulin-like growth factor 1 (Igf-1) during development results in neurological deficits that are similar to those reported for developmental hypothyroidism. This observation suggests that deficits associated with low TH during development may be the result of altered Igf-1 expression in the developing brain. To test this, timed-pregnant mice were treated with thyroid gland inhibitors from gestational day 16 (GD16) until postnatal day 21 (P21) to induce a hypothyroid state. A parallel set of untreated timed-pregnant mice were …


Temporal Localization Of Insulin-Like Growth Factor 1 (Igf1) Positive Cells In Developing Hypothyroid Brain, Shelby Anne Kline Jan 2015

Temporal Localization Of Insulin-Like Growth Factor 1 (Igf1) Positive Cells In Developing Hypothyroid Brain, Shelby Anne Kline

All Graduate Theses, Dissertations, and Other Capstone Projects

Hypothyroidism has been known to result in numerous neuroanatomical defects in the developing brain. To investigate further into the mechanism in which these defects are obtained, local brain insulin-like growth factor 1 (Igf1) was investigated in relation to the hypothyroid brain. There are many similarities between hypothyroidism and the Igf1 deficient brain. Additionally, TH (thyroid hormone) is known to interact with Igf1. Therefore, the purpose of this study was to investigate the effect of induced congenital hypothyroidism on the temporal expression of Igf1-positive cells in the brain. To investigate the relationship between TH and Igf1 in the brain, we inhibited …


The Effect Of Maternal Aldosterone Levels On The Expression Of 11b-Hsd Isoenzymes In Normal And Hypertensive Rat Placentae, Nicole Jorissen Aug 2014

The Effect Of Maternal Aldosterone Levels On The Expression Of 11b-Hsd Isoenzymes In Normal And Hypertensive Rat Placentae, Nicole Jorissen

Journal of Undergraduate Research at Minnesota State University, Mankato

In this project, we developed a Western blotting procedure to semi-quantitate levels of 11β-HSD1 and 11β-HSD2 in whole cell extracts. Then, we applied this technique to analyze the effect of reduced maternal aldosterone levels on the expression of 11β-HSD1 and 11β-HSD2 isoenzymes in the placental tissue in both normal and hypertensive rats. These enzymes control levels of glucocorticoids which compete for aldosterone’s mineralocorticoid receptor. Overstimulation of this receptor results in hypertension. If aldosterone levels decrease, levels of the enzymes controlling active glucocorticoid concentrations might change to compensate for the lowered aldosterone levels. Decreased placental 11β-HSD2 expression could affect hypertension in …