Hormone Action Research Articles

Hormonal actions in the medial preoptic area governing parental behaviour: Novel insights from new tools.

The importance of hormones in mediating a behavioural transition in mammals from a virgin or non-parenting state to parental state was established around 50 years ago. Extensive research has since revealed a highly conserved neural circuit that underlies parental behaviour both between sexes and between mammalian species. Within this circuit, hormonal action in the medial preoptic area of the hypothalamus (MPOA) has been shown to be key in timing the onset of parental behaviour with the birth of offspring. However, the mechanism underlying how hormones act in the MPOA to facilitate this change in behaviour has been unclear. Technical advances in neuroscience, including single cell sequencing, novel transgenic approaches, calcium imaging, and optogenetics, have recently been harnessed to reveal new insights into maternal behaviour. This review aims to highlight how the use of these tools has shaped our understanding about which aspects of maternal behaviour are regulated by specific hormone activity within the MPOA, how hormone-sensitive MPOA neurons integrate within the wider neural circuit that governs maternal behaviour, and how maternal hormones drive changes in MPOA neuronal function during different reproductive states. Finally, we review our current understanding of hormonal modulation of MPOA-mediated paternal behaviour in males.

Sex Differences in Blood Accumulation of Neurodegenerative-Related Proteins and Antioxidant Responses to Regular Physical Exercise

Physical activity has been demonstrated to improve cognitive function, thereby preventing/slowing neurodegenerative diseases (NDs). Biological responses to physical activity and vulnerabilities to NDs are emerging to be gender-related. Herein, known ND-associated markers (β-amyloid, tau, α-synuclein), main sex steroid hormones, antioxidant responses, and key gene transcription modulators were evaluated in the blood of physically active and sedentary women and men. In our hands, females presented higher basal erythrocytes β-amyloid and α-synuclein amounts than males. Regular physical activity was able to significantly reduce the erythrocyte content of β-amyloid in females and the tau levels in males, suggesting that these differences may be mediated by organizational actions of sex steroid hormones during development. Furthermore, despite a comparable plasma antioxidant capability (AOC) between males and females, in the latter group, physical activity significantly enhances AOC versus peroxynitrite radicals only. Finally, regular physical activity modulated the levels of transcription factor Nrf2 in erythrocytes, as well as the plasma concentration of the microRNA miR-195 and miR-153, suggesting the promotion of antioxidant/autophagic processes associated with ND-related proteins. Overall, these results could shed light on how cerebral adaptations to physical activity differ between males and females, especially with regard to blood accumulation of ND proteins and mechanisms of antioxidant responses to regular exercise.

Multiple Machine Learning Identifies Key Gene PHLDA1 Suppressing NAFLD Progression.

Non-alcoholic fatty liver disease (NAFLD) poses a serious global health threat, with its progression mechanisms not yet fully understood. While several molecular markers for NAFLD have been developed in recent years, a lack of robust evidence hampers their clinical application. Therefore, identifying novel and potent biomarkers would directly aid in the prediction, prevention, and personalized treatment of NAFLD. We downloaded NAFLD-related datasets from the Gene Expression Omnibus (GEO). Differential expression analysis and functional analysis were initially conducted. Subsequently, Weighted Gene Co-expression Network Analysis (WGCNA) and multiple machine learning strategies were employed to screen and identify key genes, and the diagnostic value was assessed using Receiver Operating Characteristic (ROC) analysis. We then explored the relationship between genes and immune cells using transcriptome data and single-cell RNA sequencing (scRNA-seq) data. Finally, we validated our findings in cell and mouse NAFLD models. We obtained 23 overlapping differentially expressed genes (DEGs) across three NAFLD datasets. Enrichment analysis revealed that DEGs were associated with Apoptosis, Parathyroid hormone synthesis, secretion and action, Colorectal cancer, p53 signaling pathway, and Biosynthesis of unsaturated fatty acids. After employing machine learning strategies, we identified one gene, pleckstrin homology like domain family A member 1 (PHLDA1), downregulated in NAFLD and showing high diagnostic accuracy. CIBERSORT analysis revealed significant associations of PHLDA1 with various immune cells. Single-cell data analysis demonstrated downregulation of PHLDA1 in NAFLD, with PHLDA1 exhibiting a significant negative correlation with macrophages. Furthermore, we found PHLDA1 to be downregulated in an in vitro hepatic steatosis cell model, and overexpression of PHLDA1 significantly reduced lipid accumulation, as well as the expression of key molecules involved in hepatic lipogenesis and fatty acid uptake, such as FASN, SCD-1, and CD36. Additionally, gene set enrichment analysis (GSEA) pathway enrichment analysis suggested that PHLDA1 may influence NAFLD progression through pathways such as Cytokine Cytokine Receptor Interaction, Ecm Receptor Interaction, Parkinson's Disease, and Ribosome pathways. Our conclusions were further validated in a mouse model of NAFLD. Our study reveals that PHLDA1 inhibits the progression of NAFLD, as overexpression of PHLDA1 significantly reduces lipid accumulation in cells and markedly decreases the expression of key molecules involved in liver lipogenesis and fatty acid uptake. Therefore, PHLDA1 may emerge as a novel potential target for future prediction, diagnosis, and targeted prevention of NAFLD.

Inclusive Exploration of Harmonizing and Alternative Treatments for Hypothyroidism

: A clinical syndrome known as hypothyroidism occurs due to a shortage of thyroid hormone as a result of decreased production, abnormal distribution, or no action of thyroid hormones. The most typical clinical symptoms included are dry skin, hair loss, weight gain, painful-prolonged periods, infertility, balance problems, slow speech, bradycardia, hypothermia, fatigue, anxiety & depression, joint pain, and indigestion. Basically, age, gender, the severity of the ailment, and a few other factors affect the various signs and symptoms of hypothyroidism. The limitations of allopathic modalities necessitate the investigation of alternative treatment options. Future healthcare initiatives for the poor world will increasingly depend on CAM approaches to these concerns because lifestyle, diet, obesity, lack of exercise, and stress are significant contributing factors to the development of hypothyroidism. This review's objective is to provide information on herbs as well as complementary and alternative medications which are grouped into five major domains: Biologically Based therapies, Manipulative body-based therapies, Mind body-based therapies, and the whole Medical system. These have traditionally been used to treat thyroid dysfunction. The distribution of diseases in emerging nations is altering as a result of globalization. Hence the existing and potential roles of CAM techniques in the general practice of medicine are illustrated in these approaches. Scientists are being compelled to consider traditional herbal medical treatments and CAM therapy in order to combat adverse medication occurrences, high treatment costs, and compliance problems thus described in this review paper.

Changes in Erythrocytes in 88 Hyperthyroid Cats

Background: There is only a limited number of studies that show alterations in erythrocytes in feline hyperthyroidism. Discrepancies between the findings of these studies may be caused by the presence of concurrent diseases and the use of various haematological analysers. Methods: This study analysed changes in red blood cells (RBCs) in 88 hyperthyroid cats without concurrent diseases, to identify associations between observed changes and to assess the influence of serum thyroxine (T4) concentration, cat age, and sex, on RBC changes. Results: Among the eighty-eight hyperthyroid cats, erythrocytosis was observed in twelve, anaemia in four, macrocytosis in two, and microcytosis in three. Three of the four cases of anaemia probably resulted from concurrent unrecognised disease. Interestingly, all cases of microcytosis were recognized in cats that had erythrocytosis. This study identified a moderate negative correlation between RBC count and mean corpuscular volume (MCV; r = −0.57, p < 0.001). Concluding, it appears that erythrocytosis may be a response to the development of microcytosis. The correlation between RBC count and MCV in hyperthyroid cats may result from the increased action of hepcidin and erythropoietin coupled with the decreased action of thyroid-stimulating hormone (TSH).

The glycoprotein hormone receptor (LGR1) influences Malpighian tubule secretion rate in Rhodnius prolixus.

In the hemipteran Rhodnius prolixus, successful post-prandial diuresis is accomplished through the synergistic actions of the peptidergic diuretic hormone RhoprCRF/DH and the biogenic amine 5-hydroxytryptamine (5-HT), and by an antidiuretic hormone RhoprCAPA-2 that terminates diuresis by inhibiting this synergy. Lateral neurosecretory cells (NSCs) in the mesothoracic ganglionic mass release RhoprCRF/DH, while midline NSCs release RhoprCAPA-2 during blood feeding. These NSCs co-express GPA2/GPB5, a conserved glycoprotein hormone involved in various physiological processes across bilaterians. This study investigates the influence of GPA2/GPB5 signaling on Malpighian tubule (MT) fluid secretion in R. prolixus. GPB5-like immunoreactivity in lateral and midline NSCs decreases following a blood meal, suggesting release and a role in diuresis. Downregulating the GPA2/GPB5 receptor LGR1 via RNA interference results in an increased basal fluid secretion rate in MTs, which is inhibited by the antidiuretic hormone RhoprCAPA-2. dsLGR1 treatment reduces the effects of RhoprCRF/DH and 5-HT on MT secretion and eliminates their synergism. RT-qPCR reveals that the transcript expression of the diuretic and antidiuretic hormone receptors are decreased in MTs of dsLGR1 injected insects, indicating that GPA2/GPB5 influences the expression of these other receptor transcripts. Downregulating LGR1 results in a smaller blood meal size and disrupts the normal time-course of diuresis. As LGR1 is the most abundantly expressed G protein-coupled receptor transcript in R. prolixus MTs, our results suggest that GPA2/GPB5 signaling has a critical role in regulating the timing and success of water retention in the unfed state, and in the complex processes associated with feeding and diuresis in R. prolixus.

Current Status of Semaglutide Injection andDevelopment Prospects in China

Obesity is a global issue that closely affects public health, and China’s obesity rate is among the highest in the world. Recently, Semaglutide injection was approved for marketing in China as the first weekly formulation for long-term weight control. This review consolidates and analyzes various types of research related to Semaglutide regarding weight loss, to comprehensively describe the different aspects of the drug. As a glucagon-like peptide 1 receptor agonists (GLP-1RA), Semaglutide works by mimicking the action of innate hormone to enhance the cell signaling activity and corresponding outcome. It has been approved to effectively reduce weight and improve weight-related factors in overweight or obese patients with a guaranteed safety profile. Comparing to traditional methods of losing weight, this medication is time and effort-saving, which makes it highly competitive in this field. Although there are still unsolved issues and challenges faced by the drug, such as high price and acceptance among doctors and patients, it is highly likely to become a new and anticipated method of weight management in China

The Interplay of the Mammalian Brain and Thyroid Hormones, and the Threat of Endocrine-Disrupting Chemicals

Introduction: During the formation of neural circuits, the developing brain demonstrates extraordinary plasticity, heavily influenced by hormones. These chemical messengers interact with specific receptors to regulate vital physiological functions. The thyroid gland plays a pivotal role in maintaining hormonal balance and guiding brain development. However, emerging threats like endocrine-disrupting chemicals (EDCs) can interfere with this intricate system. EDCs are exogenous substances that can mimic, enhance, or block the actions of endogenous hormones, disrupting hormonal signaling in the brain at various developmental stages. Exposure can impair cognitive function and behavior due to disruptions in thyroid function. Studies indicate that mixtures of EDCs negatively impact brain development, leading to lower IQ and behavioral problems. Reducing EDC exposure through regulations and public awareness is crucial, and further research is needed to elucidate their mechanisms. Conclusions: Protecting vulnerable populations, such as pregnant women and children, is essential through prompt regulatory measures.

Anti-atherosclerotic effect of incretin receptor agonists.

Incretin receptor agonists (IRAs), primarily composed of glucagon-like peptide-1 receptor agonists (GLP-1RAs) and glucose-dependent insulinotropic polypeptide receptor agonists (GIPRAs), work by mimicking the actions of the endogenous incretin hormones in the body. GLP-1RAs have been approved for use as monotherapy and in combination with GIPRAs for the management of type 2 diabetes mellitus (T2DM). In addition to their role in glucose regulation, IRAs have demonstrated various benefits such as cardiovascular protection, obesity management, and regulation of bone turnover. Some studies have suggested that IRAs not only aid in glycemic control but also exhibit anti-atherosclerotic effects. These agents have been shown to modulate lipid abnormalities, reduce blood pressure, and preserve the structural and functional integrity of the endothelium. Furthermore, IRAs have the ability to mitigate inflammation by inhibiting macrophage activation and promoting M2 polarization. Research has also indicated that IRAs can decrease macrophage foam cell formation and prevent vascular smooth muscle cell (VSMC) phenotype switching, which are pivotal in atheromatous plaque formation and stability. This review offers a comprehensive overview of the protective effects of IRAs in atherosclerotic disease, with a focus on their impact on atherogenesis.

Actions of thyroid hormones and thyromimetics on the liver.

Thyroid hormones (triiodothyronine and thyroxine) are pivotal for metabolic balance in the liver and entire body. Dysregulation of the hypothalamus-pituitary-thyroid axis can contribute to hepatic metabolic disturbances, affecting lipid metabolism, glucose regulation and protein synthesis. In addition, reductions in circulating and intrahepatic thyroid hormone concentrations increase the risk of metabolic dysfunction-associated steatotic liver disease by inducing lipotoxicity, inflammation and fibrosis. Amelioration of hepatic metabolic disease by thyroid hormones in preclinical and clinical studies has spurred the development of thyromimetics that target THRB (the predominant thyroid hormone receptor isoform in the liver) and/or the liver itself to provide more selective activation of hepatic thyroid hormone-regulated metabolic pathways while reducing thyrotoxic side effects in tissues that predominantly express THRA such as the heart and bone. Resmetirom, a liver and THRB-selective thyromimetic, recently became the first FDA-approved drug for metabolic dysfunction-associated steatohepatitis (MASH). Thus, a better understanding of the metabolic actions of thyroid hormones and thyromimetics in the liver is timely and clinically relevant. Here, we describe the roles of thyroid hormones in normal liver function and pathogenesis of MASH, as well as some potential clinical issues that might arise when treating patients with MASH with thyroid hormone supplementation or thyromimetics.

A-9-Years-Old Female with Diabetes Mellitus Type 1 with Hyperthyroidism

Diabetes Mellitus Type 1 (DMT1) and thyroid disease can occur together, which is defined as a variant of autoimmune polyglandular syndrome type 3. It is known that the action of insulin and thyroid hormones affect cellular metabolism, thyroid hormones contribute to carbohydrate metabolism and pancreatic function. Since the thyroid gland plays a central role in the regulation of metabolism, abnormal thyroid function can have a major impact on the control of diabetes and poor glycemic control can cause alterations in thyroid hormone. A female, 9 years old, with decreased consciousness. Previous medical history, polyuria, increased appetite, and drastic weight loss. She also complained of sweating even in a cold room and was often emotional. On physical examination, there was fever, shortness of breath, tachycardia, and a soft and diffused slightly enlarged thyroid gland, with no bruit on auscultation. Laboratory tests showed blood glucose levels at 739 mg/dL, HbA1c 9.2%, C-peptide 0.2 ng/mL, TSH levels 0.01 µIU/mL, FT4 levels 2.77 ng/dL, the presence of metabolic acidosis, proteinuria, glucosuria, and ketonuria. Thyroid dysfunction will have a negative effect on DM control while poor glucose control will harm the work of thyroid hormones. Improvement in glycemic control and routine insulin injection with the right dose will reduce the risk of diabetic vascular and metabolic complications onset and progression.

Decoding androgen receptor signalling: Genomic vs. non-genomic roles in prostate cancer

The Androgen receptor (AR) is known to manifest the biological actions of male sex hormones. Androgens are now known to exert a multitude of responses, sometimes contrasting, in physiological and pathological conditions. Several groups have attempted to explain the underlying mechanisms of these varying androgen responses, including the non-genomic actions of androgens. These actions lead to increased activity of pro-proliferative signal transduction pathways, resulting in rapid molecular effects that cannot be explained by the conventional model in which AR functions as a transcription factor to modulate target gene expression [1,2].This spotlight article examines Safi et al.'s research on the androgen receptor (AR) in prostate cancer, revealing that low androgen levels drive proliferation via non-genomic mechanisms involving AR monomers, while high levels suppress growth through genomic actions with AR dimers. These findings challenge current paradigms and suggest novel therapeutic strategies targeting both AR forms, particularly focusing on the role of AR monomers in cancer progression and treatment resistance.

Experimentally Elevated Levels of Testosterone Advance Daily Onset of Activity in Short-Day Housed Male House Sparrows (Passer domesticus).

Seasonal changes in sleep/wake cycles and behaviors related to reproduction often co-occur with seasonal fluctuations in sex hormones. Experimental studies have established that fluctuations in circulating testosterone mediate circadian rhythms. However, most studies are performed under constant lighting conditions and fail to investigate the effects of testosterone on the phenotypic output of circadian rhythms, that is, chronotype (daily activity patterns under light:dark cycles). Here, we experimentally elevated testosterone with implants during short nonbreeding daylengths in male house sparrows (Passer domesticus) to test if observed seasonal changes in chronotype are directly in response to photoperiod or to testosterone. We fitted individuals with accelerometers to track activity across treatment periods. Birds experienced three treatments periods: short day photoperiods before manipulation (SD), followed by testosterone implants while still on short days (SD + T). Implants were then removed. After a decrease in cloacal protuberance size, an indicator of low testosterone levels, birds were then photostimulated on long days (LD). Blood samples were collected at night, when testosterone peaks, to compare testosterone levels to daily onset/offset activity for experimental periods. Our results indicate that experimentally elevated testosterone under short nonbreeding photoperiods significantly advanced daily onset of activity and total daily activity relative to daylength. This suggests that testosterone, independent of photoperiod, is responsible for seasonal shifts in chronotypes and daily activity rhythms. These findings suggest that sex steroid hormone actions regulate timing of daily behaviors, likely coordinating expression of reproductive behaviors to appropriate times of the day.

7492 Fibroblast Growth Factor 21 In The Diagnosis And Treatment Of Metabolic Disorders

Abstract Disclosure: H.M. Heshmati: None. H.S. Abu-Lebdeh: None. Background: Fibroblast growth factor 21 (FGF21), a member of the human FGF superfamily, is a 181 amino acid peptide hormone primarily produced by the liver. The gene of FGF21, located on chromosome 19, was cloned in 2000. FGF21 is involved in the maintenance of metabolic homeostasis. This review presents an update on the relevance of FGF21 in the diagnosis and treatment of metabolic disorders including obesity, nonalcoholic fatty liver disease (NAFLD), dyslipidemia, and type 2 diabetes. Methods: A systematic search of literature was conducted using the search terms fibroblast growth factor 21, obesity, nonalcoholic fatty liver disease, dyslipidemia, and type 2 diabetes. Results: FGF21 is a stress hormone with effects on energy expenditure and metabolism of lipids and glucose. FGF21 exerts its endocrine action in the central nervous system and adipose tissue. The serum FGF21 levels in normal subjects increase with aging. Stressful conditions (e.g., fasting status, protein restriction, exercise, metabolic disorders, kidney diseases, cardiovascular diseases, and sepsis) increase FGF21 secretion. Serum FGF21 levels are increased in obesity, NAFLD, dyslipidemia, and type 2 diabetes. Some of these patients may have a state of FGF21 resistance. The resistance to FGF21 is related, at least in part, to the presence of high circulating levels of fibroblast activation protein, a protease that inactivates FGF21. It has been suggested that the exercise-induced weight loss can be due to increased FGF21 secretion and decreased FGF21 resistance in adipose tissue. Serum FGF21 level has the potential to be used as a biomarker for early diagnosis of metabolic disorders (e.g., NAFLD and type 2 diabetes). Based on different metabolic properties of FGF21, FGF21-based therapy has been considered as an attractive approach for the treatment of metabolic disorders. Since native FGF21 has poor pharmacodynamic properties (e.g., short half-life and proteolytic cleavage by proteases), long-acting FGF21 analogs (e.g., LY2405319, PF-05231023, pegozafermin, AKR-001, and LLF580) have been synthesized and tested in clinical trials for the treatment of obesity, NAFLD, dyslipidemia, and type 2 diabetes. The available results show that FGF21 analogs can reduce body weight, liver fat, blood lipids, and fasting insulin/insulin resistance. Overall, the treatment with these analogs is safe and well tolerated. Conclusion: FGF21 is a predominantly liver-derived peptide hormone regulating energy expenditure and metabolism of lipids and glucose. Serum FGF21 levels are increased in several metabolic disorders including obesity, NAFLD, dyslipidemia, and type 2 diabetes. FGF21 is an attractive target for the treatment of these metabolic disorders. Despite some promising results observed with the use of FGF21 analogs, more clinical studies are needed before recommending FGF21-based therapies in metabolic disorders. Presentation: 6/2/2024

8142 Endocrine Considerations Prior to Pituitary Tumor Resection

Abstract Disclosure: P. Einafshar: None. T. Delibasi: None. Endocrine Considerations in Pituitary Tumor Resection Introduction: Diabetes Insipidus (DI) is an endocrine condition involving a disturbance to the action of Anti-Diuretic Hormone (ADH) resulting in polyuria, and polydipsia with complications such as severe water and electrolyte disturbances. It can be classified into Central DI which affects the secretion of ADH or Nephrogenic DI which affects peripheral ADH receptors in Distal Convoluted Tubules (DCTs) in the renal system. Both subtypes however present similarly and are usually known to be transient. It is important to consider the most common etiologies contributing to both central and nephrogenic DI as severe complications may arise if not diagnosed and treated promptly. The most important step is to monitor and manage water and electrolytes and avoid excessive water loss which can lead to irreversible complications. This can be accomplished by introducing synthetic ADH called DDAVP or Desmopressin. Case Description: A 57-year-old female was admitted in preparation for a supra-orbital resection of a suprasellar mass. Two hours post-procedure, she was found to have an increase in urine output with her labs notable for a significant acute increase in serum sodium and a decrease in urine osmolality. Upon emergent Endocrinology evaluation, due to concerns of Acute Diabetes Insipidus in the setting of insult to the pituitary stalk, she was started on emergent treatment with IV DDAVP. Her course was complicated with persistent DI resulting in a case of permanent DI requiring out-patient daily treatments with DDAVP. Discussion: Injury to the pituitary stalk resulting in various endocrine abnormalities has been studied involving a trans-sphenoidal resection of pituitary tumors, but there is a paucity of cases reported when patients undergo a supra-orbital surgical approach. It is vital for Endocrinology and Neurosurgical services to be aware of this phenomenon, and a multi-disciplinary approach to patient management should be considered. Furthermore, close follow-up of pituitary hormones in the post-operative setting is imperative in order to avoid severe complications, such as brain damage or poor mental status. We hope to educate residents and fellows about this phenomenon that is rarely reported in the literature but can have profound effects on patient’s quality of life if not considered by the consulting Endocrinology team. References Christ-Crain, M., Winzeler, B., & Refardt, J. (2021). Diagnosis and management of diabetes insipidus for the internist: an update. Journal of internal medicine, 290(1), 73-87. Mutter, C. M., Smith, T., Menze, O., Zakharia, M., & Nguyen, H. (2021). Diabetes insipidus: pathogenesis, diagnosis, and clinical management. Cureus, 13(2). Presentation: 6/1/2024

8596 Brain Type 3 Deiodinase Is Induced in Two Disease Models That Lead to Cognitive Impairment: Liver Dysfunction and Alzheimer Disease

Abstract Disclosure: S. Wajner: None. T. Oliveira: None. M. Dreher: None. R. Ribeiro: None. C. Gonçalves: None. M.R. Alveres-da-Silva: None. Thyroid hormone is the leading regulator of cell energy production in most tissues, mainly the brain. While the activation process of T4 into T3 depends on D1 and D2 deiodinases, type 3 is the main enzyme that inactivates T3. Several mechanisms, among them oxidative stress, led by disease, imbalances and induces D3, diminishing T3 levels. The response of D3 in the brain in the context of different disease models has yet to be studied. Here we evaluated D3 induction in the brain in two animal disease models, one systemic and the other local. Methodology: To the metabolic dysfunction-associated steatosis liver disease model Male/adult Sprague Dawley rats (n=20) were assigned to control group (standard diet-2.93kcal/g) or high-fat-diet group (CDHF-4.3kcal/g). In the streptozotocin-induced (STZ) Alzheimer's model Adult Wistar rats (n=16) were allocated to the control group (5uL of citrate) or 5uL of streptozotocin. Sham animals were used as controls. D3 expression, oxidative stress parameters, endoplasmic stress and mitochondrial amount measured in the brain. Levels of D3 increased in the brain (∼30% in each group, P<0.0001) in both MASLD and STZ groups. Cerebral tissue from both groups had augmented carbonyl levels (P<0.001) and reduced sulfhydryl (P<0.001). Glutathione was diminished. Antioxidant defenses endoplasmic reticulum function and mitochondrial concentration were altered (P=0.001). The augmented T3 inactivation by D3 dysfunction in brain due to oxidative stress disrupts ER-mitochondrial contact interaction, changing the function of organelles in both brain disease models, shedding light to new mechanisms of action of thyroid hormone in severe brain disease. Presentation: 6/3/2024

8026 Growth Hormone Receptor (GHR) is Independently Associated with Body Composition and Glycemic Measures in Youth with Type 2 Diabetes (T2D)

Abstract Disclosure: C. Lu: None. D. Wolfs: None. L. El ghormli: None. L.M. Laffel: None. M. Patti: Advisory Board Member; Self; Fractyl Health. Consulting Fee; Self; AstraZeneca, Hamni, MBX Biosciences. Grant Recipient; Self; Dexcom. E. Isganaitis: None. Background: T2D is more severe in youth than in adults, with growth and puberty as potential drivers. Growth hormone (GH) action, which peaks during puberty, also regulates carbohydrate metabolism. We previously showed that higher plasma levels of GHR are associated with hyperglycemia, insulin resistance, and decreased insulin secretion in youth with T2D. Plasma GHR is higher in obesity, and reductions in GHR after bariatric surgery may mediate improvements in glycemia. The association of GHR with body composition in youth with T2D has not been previously studied. Hypothesis: We hypothesize that the association of GHR with glycemic outcomes in youth with T2D is mediated by differences in body composition, and that associations between GHR and body composition differ by sex. Methods: Utilizing plasma samples from Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) study (N=398), we examined association of plasma GHR (ELISA; ng/mL) with a) body composition measures including zBMI, absolute lean mass (kg), percent body fat (dual-energy x-ray absorptiometry), and b) glycemic outcomes including hemoglobin A1c (HbA1c), fasting glucose (mg/dL), 1/fasting C-peptide (mL/ng), C-peptide index (ng/mL per mg/dL), and C-peptide oral disposition index (CODI; mL/uU x ng/mL per mg/dL), stratified by sex. Linear regressions were adjusted for age, race/ethnicity, and Tanner stage in the base models, with additional adjustments for HbA1c, zBMI, lean mass, or percent fat. Results: This subcohort of youth with T2D from the TODAY study included 150 males and 248 females, mean age 13.9 ± 2.0 years. Females had lower zBMI (+2.2 ± 0.4 vs. +2.3 ± 0.5, p=0.005), lower lean mass (51 ± 10 vs. 59 ± 14, p<0.001), and higher percent body fat (39 ± 5 vs. 34 ± 6, p<0.001). Higher log2 GHR was associated with higher zBMI (B=0.44, SE=0.04, p<0.001), higher lean mass (B=4.3, SE=1.2, p<0.001), and higher percent fat (B=4.4, SE=0.7, p<0.001), even after adjustment for HbA1c, and without sex-specific differences. Higher log2 GHR was associated with higher HbA1c (B=0.35, SE=0.08, p<0.001), higher fasting glucose (B=9.0, SE=2.6, p<0.001), lower 1/fasting C-peptide (B=-0.17, SE=0.01, p<0.001), and lower CODI (B=-0.001, SE=0.001, p=0.02). These associations did not change with further adjustments for zBMI, lean mass, or percent fat, suggesting that associations between GHR and glycemia are independent of obesity or body composition. In analyses stratified by sex, the effect of GHR on CODI was attenuated after adjustment for lean mass in males only. Conclusion: Plasma GHR is independently associated with body composition and glycemia in youth with T2D. There were no sex differences in associations of GHR with HbA1c and insulin resistance. However, the association of GHR with beta cell function may be mediated by lean mass in boys but not in girls, although power was more limited in the sex-stratified analyses. Presentation: 6/3/2024

7407 Normosmic Idiopathic Hypogonadotropic Hypogonadism in Women: A Case Report and Comprehensive Review

Abstract Disclosure: E.G. Bustamante: None. M. Sulehri: None. I. Patoli: None. A. Karunakaran: None. Normosmic Idiopathic Hypogonadotropic Hypogonadism (nIHH) in Women: A Case Report and Literature ReviewIntroduction: IHH is a rare genetic disorder affecting gonadotropic-releasing hormone (GnRH) production and/or action, resulting in diminished sex steroid levels. Characterized by the absence of spontaneous pubertal development. In women, it manifests with normal adrenarche but absent thelarche and menarche. Our case highlight a late diagnosis of IHH in a 34-year-old woman with primary amenorrhea. Case report: A 34 year old lady with a history of primary amenorrhea sought evaluation. At age 16, she underwent assessment for short stature and primary amenorrhea, denying anosmia, headache, visual disturbances. Evaluation revealed bone age concordant with chronological age and normal MRI Brain. Pelvic ultrasound (US) showed small premenarchal uterus and ovaries. She initiated oral contraceptive pills (OCP) and experienced regular menses. Seeking fertility assistance at age 24, a normal Hysterosalpingogram was followed by successful delivery of twins after ovarian stimulation. Post-delivery menses did not resume and OCP was not restarted. Family history revealed a sister with irregular periods requiring OCP.Subsequently workup at age 30 showed Estradiol 22 pg/ml, FSH/LH 4.1/2.3 mUI/mL; normal PRL, TFT, DHEAS, 17OHP. Repeat Pelvic US showed normal uterus, endometrial stripe normal at 0.24 cm and non-visualized ovaries. PCOS testing negative for hyperandrogenism. Progesterone challenge resulted in no withdrawal bleeding. Brain MRI demonstrated a 2.2 x 1.3 mm hypoenhancing ovoid mass in the pars Intermedia of the pituitary gland suggestive of pituitary microadenoma. Pituitary axis hormonal testing was normal. Karyotype revealed 46 XX (normal female). Genetic evaluation identified a pathogenic variant (p.R35C) in GNRH1 gene. Her final diagnosis: nIHH. Discussion HH is diagnosed in 5% of all women with primary amenorrhea and is divided into 2 major categories: Kallmann syndrome and nIHH. The majority of known causes of HH can be attributed to mutations in KAL1, FGFR1, or GNRHR. The p.R35C variant has been associated with autosomal dominant nIHH. Diagnosis involves clinical suspicious, low LH/FSH and sex steroid levels, normal hypothalamic–pituitary imaging, and exclusion of differentials.Treatment goal for female focus on regular breast and uterine development, as well as the capability to conceive. Use of hormonal replacement therapy and/or gonadotropins or pulsatile GnRH for ovarian stimulation are essential. ConclusionWhile IHH predominantly affects men, limited literature explores its manifestation in women and its impact on fertility. The identification of a GNRH1-related nIHH variant highlights the role of genetic testing in specific HH diagnoses. Failure to diagnose in adolescence may compromise women overall well-being Presentation: 6/1/2024

7308 A Case of Thyroid Hormone Resistance Associated With a Novel Mutation in the THRA Gene

Abstract Disclosure: J.A. Siddiqui: None. M. Barbosa: None. V. Fettig: None. C.J. Romero: None. Introduction: Thyroid hormone resistance (THR) is a syndrome leading to decreased response of target organs to thyroid hormone. Normal thyroid hormone action is mediated by thyroid hormone nuclear receptors and is essential for normal development and metabolism. Two isoforms are encoded by the thyroid hormone receptor α and β genes (THRA and THRB). Mutations in THRB are commonly reported with limited cases of THRA mutations. We report a 15-month-old and her mother with a pathogenic variant in the THRα receptor leading to thyroid hormone resistance. CASE: A 15-month-old ex-39-week gestation female was born small for gestational age (birth weight: 2450 grams,3rd %ile and birth length: 17 inches,1st %ile). The newborn screen was normal. She presented with macroglossia, low tone and global developmental delay. She had severe constipation complicated by rectal prolapse that required surgical correction. There are multiple relatives (mother, maternal half-brother and maternal grandparents) with neurodevelopmental issues. The mother’s previous genetic evaluation was non-diagnostic. Mother reports a thyroid condition but without treatment. The patient was initially referred to genetics and whole exome sequencing revealed a heterozygous c.1205 T>C p. (L402P) variant in the THRα gene, which was maternally inherited and reported as a variant of uncertain significance. On physical exam, Heart rate was 112 bpm; height <1%ile (Z-score -3.22 SD), weight 3%ile (Z-score -1.89 SD). Patient has a wide anterior fontanelle (4x3 cm), macroglossia and delayed teeth eruption. Other exam findings: non-palpable thyroid and postaxial polydactyly on the 5th digit of the right toe. Thyroid hormone testing: normal TSH 1.829 uIU/mL, low total T4 4.4 mcg/dL, low Free T4 of 0.58 ng/dL and high free T3 of 4.24 pg/mL. Levothyroxine treatment was initiated(25 mcg daily). After 1 month treatment, TSH level was 0.23 uIU/mL, total T4 was 6.1 mcg/dL and low reverse T3 of 5.8 ng/dL. DISCUSSION: Thyroid hormone resistance due to THRα mutations are rare and under-recognized. The main clinical phenotype includes growth retardation, delayed development, decreased muscle tone, delayed tooth eruption and constipation. Unlike patients with THRβ mutations, the hypothalamus-pituitary-thyroid axis in patients with THRα mutations is minimally affected with a normal TSH level. Total T3 levels are elevated with slightly low total T4 and free T4:T3 ratio is low. Treatment with levothyroxine leads to suppressions of TSH levels, therefore confirming intact central T3 feedback loop. Reports, however, show minor clinical improvements with treatment; therefore further research is needed in these patients to explore more effective therapeutic options. We present a case of a novel congenital THRA mutation leading to a clinical phenotype consistent with THR. She continues care in our clinic with hopes to further study her mutation. Presentation: 6/2/2024

8398 Non-genomic Effects of Thyroid Hormones on the Breast Cancer Microenvironment

Abstract Disclosure: L. Drago: None. S. Shahrivari: None. N. Schwenk: None. P. Nelson: None. H. Hosseini: None. C. Spitzweg: None. Objective: Mesenchymal stem cells (MSCs) are central players in the genesis of the breast cancer tumor microenvironment and play a role in tumor initiation, progression, invasion, metastasis, angiogenesis as well as resistance to treatment. There is increasing evidence for an association between thyroid function and breast cancer risk. Thyroid hormone effects mediated through the αvβ3 integrin, a thyroid hormone receptor, are proposed as a pathophysiologic link to this observation. Methods: To evaluate the migratory behavior of MSCs in the presence or absence of thyroid hormone treatment in response to tumor-derived signals, a 3D migration assay was performed. MSCs pretreated with T3 (1nM) or T4 (1μM) with or without tetrac (100nM) (T4 analog, specific inhibitor of αvβ3 integrin-mediated thyroid hormone action) for 24 h were subjected to a gradient between serum-free medium and serum-free conditioned medium (CM) from five different breast cancer cell lines representative of different breast cancer subtypes including T47D as Luminal B, MCF7 as Luminal A, BT-474 and MDA-MB-453 as HER2, and MDA-MB-231 as Triple negative subtype. Results: MSCs subjected to a gradient between CM derived from each breast cancer cell line and serum-free medium showed directed chemotaxis towards tumor-CM with a significantly increased forward migration index (FMI) and center of mass (CoM). This migratory behavior was significantly enhanced upon treatment with T3 or T4. The cellular migration towards tumor-CM of MDA-MB-453, BT-474, and T47D was more effective upon MSC treatment with T3, but less so with T4. MSCs treated with T4 showed a better migratory performance towards the CM of MCF7 and MDA-MB-231. Except for T47D-CM, additional treatment with tetrac inhibited the enhanced effects of T3 and T4 on MSC migration demonstrating that this effect is mediated through αvβ3 integrin. Conclusion: Our preliminary in vitro data on the effects of thyroid hormones T3 and T4, and the thyroid hormone metabolite tetrac on MSC migration shows a distinct behaviour of MSCs in the presence of either T3 or T4 depending on the breast cancer cell subtype, suggesting a role of non-genomic, integrin αvβ3-mediated thyroid hormone action on MSC biology within the breast tumor microenvironment that warrants further investigation. Presentation: 6/3/2024