For my dissertation research I explored the diversity and functional evolution of steroid hormone receptors (SRs) in animals and the physiological implications of the evolution of antifreeze proteins in Antarctic notothenioid fishes. For the former, I discovered multiple new SRs from the vast and under-sampled swath of animal diversity known as invertebrates. I used the sequences of these and other newly discovered related receptors in combination with genomic data and molecular phylogenetic techniques to revise the understanding of the evolutionary history of this important gene family. While previous studies have suggested that vertebrate SR diversity arose from a gene duplication in an ancestor of all bilaterian animals, my work presents strong evidence that this duplication occurred much later, at the base of the chordates. Furthermore, to determine the implications of added diversity and a revised phylogeny on inferences of the functional evolution of SRs, I functionally characterized heretofore-unknown SRs from hemichordates, an acoelomate flatworm, and a chaetognath and statistically reconstructed and functionally characterized ancestral SRs. My results expand the known sequence and functional repertoire of SRs in animals while reinforcing the previous inference that all SRs evolved from an estrogen-sensitive ancestral receptor. I also explored the consequences of the evolution of antifreeze proteins in Antarctic notothenioid fishes, a crucial adaptation to their icy, polar environment. These special proteins adsorb to ice crystals that enter a fish's body and prevent further growth, thereby averting death. I discovered that, in addition to their lifesaving growth-inhibiting ability, AFPs also prevent the melting of internal ice crystals at temperatures above the expected equilibrium melting point. Together with a decade-long temperature record of one of the coldest fish habitats on earth, my experimental results show that the evolution and expression of antifreeze proteins is accompanied by a potentially detrimental consequence: the lifelong accumulation of ice inside these fishes' bodies. This dissertation includes previously published co-authored material as well as unpublished co-authored material. / 2017-01-14

abstract: Women are exposed to numerous endogenous and exogenous hormones across the lifespan. In the last several decades, the prescription of novel hormonal contraceptives and hormone therapies (HTs) have resulted in aging women that have a unique hormone exposure history; little is known about the impact of these hormone exposures on short- and long- term brain health. The goal of my dissertation was to understand how lifetime hormone exposures shape the female cognitive phenotype using several innovative approaches, including a new human spatial working memory task, the human radial arm maze (HRAM), and several rodent menopause models with variants of clinically used hormone treatments. Using the HRAM (chapter 2) and established human neuropsychological tests, I determined males outperformed females with high endogenous or exogenous estrogen levels on visuospatial tasks and the spatial working memory HRAM (chapter 3). Evaluating the synthetic estrogen in contraceptives, ethinyl estradiol (EE), I found a high EE dose impaired spatial working memory in ovariectomized (Ovx) rats, medium and high EE doses reduced choline-acetyltransferace-immunoreactive neuron population estimates in the basal forebrain following Ovx (chapter 4), and low EE impaired spatial cognition in ovary-intact rats (chapter 5). Assessing the impact of several clinically-used HTs, I identified a window of opportunity around ovarian follicular depletion outside of which the HT conjugated equine estrogens (CEE) was detrimental to spatial memory (chapter 6), as well as therapeutic potentials for synthetic contraceptive hormones (chapter 9) and bioidentical estradiol (chapter 7) during and after the transition to menopause. Chapter 6 and 7 findings, that estradiol and Ovx benefitted cognition after the menopause transition, but CEE did not, are perhaps due to the negative impact of ovarian-produced, androstenedione-derived estrone; indeed, blocking androstenedione’s conversion to estrone prevented its cognitive impairments (chapter 8). Finally, I determined that EE combined with the popular progestin levonorgestrel benefited spatial memory during the transition to menopause, a profile not seen with estradiol, levonorgestrel, or EE alone (chapter 9). This work identifies several cognitively safe, and enhancing, hormonal treatment options at different time points throughout female aging, revealing promising avenues toward optimizing female health. / Dissertation/Thesis / Doctoral Dissertation Psychology 2015

abstract: Obesity and its underlying insulin resistance are caused by environmental and genetic factors. DNA methylation provides a mechanism by which environmental factors can regulate transcriptional activity. The overall goal of the work herein was to (1) identify alterations in DNA methylation in human skeletal muscle with obesity and its underlying insulin resistance, (2) to determine if these changes in methylation can be altered through weight-loss induced by bariatric surgery, and (3) to identify DNA methylation biomarkers in whole blood that can be used as a surrogate for skeletal muscle. Assessment of DNA methylation was performed on human skeletal muscle and blood using reduced representation bisulfite sequencing (RRBS) for high-throughput identification and pyrosequencing for site-specific confirmation. Sorbin and SH3 homology domain 3 (SORBS3) was identified in skeletal muscle to be increased in methylation (+5.0 to +24.4 %) in the promoter and 5’untranslated region (UTR) in the obese participants (n= 10) compared to lean (n=12), and this finding corresponded with a decrease in gene expression (fold change: -1.9, P=0.0001). Furthermore, SORBS3 was demonstrated in a separate cohort of morbidly obese participants (n=7) undergoing weight-loss induced by surgery, to decrease in methylation (-5.6 to -24.2%) and increase in gene expression (fold change: +1.7; P=0.05) post-surgery. Moreover, SORBS3 promoter methylation was demonstrated in vitro to inhibit transcriptional activity (P=0.000003). The methylation and transcriptional changes for SORBS3 were significantly (P≤0.05) correlated with obesity measures and fasting insulin levels. SORBS3 was not identified in the blood methylation analysis of lean (n=10) and obese (n=10) participants suggesting that it is a muscle specific marker. However, solute carrier family 19 member 1 (SLC19A1) was identified in blood and skeletal muscle to have decreased 5’UTR methylation in obese participants, and this was significantly (P≤0.05) predicted by insulin sensitivity. These findings suggest SLC19A1 as a potential blood-based biomarker for obese, insulin resistant states. The collective findings of SORBS3 DNA methylation and gene expression present an exciting novel target in skeletal muscle for further understanding obesity and its underlying insulin resistance. Moreover, the dynamic changes to SORBS3 in response to metabolic improvements and weight-loss induced by surgery. / Dissertation/Thesis / Appendix A / Appendix B / Appendix C / Appendix D / Appendix G / Doctoral Dissertation Biology 2017

abstract: In wild birds, the stress response can inhibit the activity of the innate immune system, which serves as the first line of defense against pathogens. By elucidating the mechanisms which regulate the interaction between stress and innate immunity, researchers may be able to predict when birds experience increased susceptibility to infections and can target specific mediators to mitigate stress-induced suppression of innate immune activity. Such elucidation is especially important for urban birds, such as the House Sparrow (Passer domesticus), because these birds experience higher pathogen prevalence and transmission when compared to birds in rural regions. I investigated the role of corticosterone (CORT) in stress-induced suppression of two measures of innate immune activity (complement- and natural antibody-mediated activity) in male House Sparrows. Corticosterone, the primary avian glucocorticoid, is elevated during the stress response and high levels of this hormone induce effects through the activation of cytosolic and membrane-bound glucocorticoid receptors (GR). My results demonstrate that CORT is necessary and sufficient for stress-induced suppression of complement-mediated activity, and that this relationship is consistent between years. Corticosterone, however, does not inhibit complement-mediated activity through cytosolic GR, and additional research is needed to confirm the involvement of membrane-bound GR. The role of CORT in stress-induced inhibition of natural antibody-mediated activity, however, remains puzzling. Stress-induced elevation of CORT can suppress natural antibody-mediated activity through the activation of cytosolic GR, but the necessity of this mechanism varies inter-annually. In other words, both CORT-dependent and CORT-independent mechanisms may inhibit natural antibody-mediated activity during stress in certain years, but the causes of this inter-annual variation are not known. Previous studies have indicated that changes in the pathogen environment or food availability can alter regulation of innate immunity, but further research is needed to test these hypotheses. Overall, my dissertation demonstrates that stress inhibits innate immunity through several mechanisms, but environmental pressures may influence this inhibitory relationship. / Dissertation/Thesis / Doctoral Dissertation Biology 2017

HMb, metabólito da leucina, utilizado para aumentar a síntese protéica. Investigamos o efeito do HMb sobre o eixo somatotrófico, bem como o mRNA de IGF-I e miostatina muscular. Ratos tratados com HMb (320 mg/Kg de peso corporal /mL de salina-0,9%), ou salina (controle), gavagem, 4 semanas, decapitados, sangue para avaliação sérica: insulina (RIE), glicose (colorimetria) e IGF-I (RIE). Extração de RNA total, para avaliação do mRNA de IGF-I e miostatina (Fígado, músculo extensor digital longo, Sóleo), avaliação da expressão do mRNA do GH, por Northern Blot, e expressão do GH ,Western blotting (hipófise). Dados analisados pelo teste-T de Student (P<0,05). Tratamento aumentou o conteúdo de mRNA de GH (> 60%), da proteína GH (>20%), do mRNA do IGF-I (~24%), da concentração sérica de IGF-I (p<0,05), indicando uma ativação do eixo somatotrófico pelo HMb, sem alterações no mRNA de miostatina e IGF-I muscular, ainda um aumento da insulina (~2x), sem alterações na glicose sérica, resultado do efeito hiperglicemiante do GH, ou um efeito direto do HMb na secreção de insulina. / HMb, metabolite of leucine, used to increase protein synthesis. Evaluate the effect HMb on the somatotrophic axis activity, as well as muscle mRNA IGF-I and myostatin. Rats treated with HMb (320 mg / kg body weight / mL of saline-0, 9%) or saline (control), gavage, 4 weeks, decapitated, blood for evaluation of serum: insulin (RIA), glucose (colorimetric) and IGF-I (RIA). Extraction of RNA total, for evaluation the mRNA IGF-I and myostatin (liver, muscle extensor digitalis longus (EDL) and soleus), evaluation of the GH mRNA expression of by Northern blot, and GH content, western blotting (pituitaries). Data analyzed by Student t-test (P <0.05). HMb treatment increased the content of GH mRNA (> 60%), GH (> 20%), IGF-I mRNA (~ 24%), IGF-I (p <0.05), indicates that the somatotrophic axis activity is increased by the HMb, without changes in mRNA of myostatin and muscle IGF-I, insulin also increased (~ 2x), without changes in serum glucose, hyperglycemiant result of the effect of GH or a direct effect of HMb in the secretion of insulin.

Bakgrund: Diabetes är en av de sjukdomar som är mest växande globalt. I Sverige är det över 400 000 människor som lever med diabetes. Diabetessjukdomen finns i olika former och de vanligaste formerna är diabetes typ 1 och diabetes typ 2. Risken att bli drabbad av den sjukdomen ökar vid fetma, tobaks- och alkoholkonsumtion. Därför kan det bli nödvändigt att genomföra livsstilsförändring för att förbättra den mentala och fysiska hälsan hos personer som lever med diabetes typ 2.   Syfte: Syftet med denna studie var att beskriva hur personer med diabetes typ 2 upplever att genomgå livsstilsförändringar till följd av sjukdomen. Syftet var också att beskriva datainsamlingsmetoderna i de inkluderade artiklarna i resultatet.   Metod: En litteraturstudie med en deskriptiv design som baserades på 14 kvalitativa vetenskapliga artiklar.   Huvudresultat: Resultatet för denna litteraturstudie baserades på möjligheter och svårigheter som påverkade upplevelsen av att genomgå livsstilsförändringar hos personer med diabetes typ 2. Utifrån möjligheter har fyra subteman identifierat: Kost och motion som motivationsfaktorer, erhållen kunskap, betydelsen av stöd från omgivningen och att ta personligt ansvar. I huvudteman svårigheter presenterades dessa subteman: Kost- och motions påverkan på det sociala och vardagliga livet, brist på kunskap samt krav och inre kamp.   Slutsats: Flera personer fick blandade känslor utifrån upplevda möjligheter och svårigheter som de har stött på under livsstilsförändringen. Det blir viktigt att sjukvårdspersonal får en bättre helhetsförståelse kring patienters olika upplevelser av att genomgå en livsstilsförändring för att kunna optimera en personcentrerad vård, egenvårdsinsatser och tillgodose patienters egenvårdsbehov.

Orientadores: Munir S. Skaf, Igor Polikarpov / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-10T11:55:27Z (GMT). No. of bitstreams: 1 Martinez_Leandro_D.pdf: 4821126 bytes, checksum: 7d01e9286d04e5bd7cd7cb84abe10476 (MD5) Previous issue date: 2007 / Resumo: Receptores nucleares (NRs) formam uma superfamília de fatores de transcrição. Os receptores de hormônios mais conhecidos são os receptores do ácido retinóico, do estrógeno, da progesterona, os dos glucocorticóides e os receptores do hormônio tireoideano (TRs). Os NRs são formados por três domínios: um domínio N-terminal que contém um fator de transcrição, um domínio de ligação com o DNA e um domínio ao qual os hormônios se ligam (LBD). O domínio de ligação com os hormônios é o maior dos três, sendo formado por cerca de 260 resíduos, 12 a-hélices e poucas e pequenas folhas-b. Aqui apresentamos estudos da dinâmica dos LBDs dos TRs. Os TRs são responsáveis pelo controle do metabolismo basal, pelo consumo de gorduras e ácidos graxos, e pelo controle da atividade cardíaca. Há fundamentalmente duas isoformas de TRs: TRa e TRb. Ligantes seletivos para uma das isoformas têm um grande valor farmacológico. As estruturas cristalográficas dos LBDs, no entanto, têm permitido apenas uma apreciação parcial das relações entre a estrutura e a função dos TRs. Aspectos dinâmicos dos LBDs parecem ter uma importância fundamental em vários mecanismos fisiológicos. Neste trabalho, apresentamos estudos de vários aspectos da dinâmica molecular dos LBDs dos receptores do hormônio tireoideano. Técnicas não-convencionais de simulações de dinâmica molecular são usadas, e novas metodologias e técnicas de análise de dados são propostas. Os estudos se iniciam pela definição dos mecanismos preferenciais de dissociação dos ligantes. O caminho preferencial de dissociação e seu fundamento estrutural são determinados. Em seguida, são feitos estudos das razões estruturais e dinâmicas da seletividade dos ligantes Triac e GC-1. No caso do Triac, as estruturas cristalográficas são aparentemente contraditórias com a seletividade observada. As simulações resolvem essa aparente contradição, e sugerem que são fatores entrópicos que fazem do Triac um ligante b-seletivo. No caso do GC-1,as simulações e as estruturas cristalográficas mostraram que são interações entre resíduos do LBD que conferem a b-seletividade. Estudos da desnaturação dos TRs por temperatura também são apresentados. As simulações mostram que a desnaturação dos LBDs ocorre primeiro pelo desenovelamento das hélices. A expansão da estrutura com a exposição do seu núcleo hidrofóbico ocorre apenas em uma segunda etapa. O resultado é coerente com estudos de dicroísmo circular nos quais uma grande estabilização do LBD pela associação do Triac é observada. Por fim, estudos dos mecanismos de difusão térmica (redistribuição de energia vibracional) dos LBDs são apresentados. Estes estudos mostram que existem três mecanismos básicos de transferência de energia cinética em proteínas. Diferentes resíduos têm diferentes contribuições para a transferência de energia. No caso dos LBDs dos receptores do hormônio tireoideano, as Argininas possuem um papel particularmente importante. Os resíduos que se destacam para a difusão térmica possuem relevância funcional, mostrando que os mecanismos observados podem ser importantes para a estabilidade dos LBDs pela dissipação de perturbações cinéticas. / Abstract: Nuclear receptors (NRs) comprise a superfamily of transcription factors. The receptors of the most well known hormones are the retinoic acid, estrogen, progesterone, glucocorticois and the thyroid hormone receptors (TRs). NRs are composed by three domains: An N-terminal domain, that contains a transcription factor, a DNA binding domain, and a ligand binding domain (LBD). The LBD is the largest of the three domains, and it is composed by roughly 260 residues, 12 a-helices and a few small b-sheets. Here we study the dynamics of the LBDs of TRs. TRs are responsible for the control of the basal metabolism, the consumption of fat, and for the control of cardiac activity. There are two TR isoforms: TRa and TRb. Ligands that are selective to one or other isoform have important pharmaceutical value. Crystallographic structures of the LBDs, however, have provided only limited information on the relationships between structure and function of TRs. Dynamic mechanisms of the LBDs seem to be involved in several physiological processes. In this work, we describe various aspects of the molecular dynamics of the LBDs of TRs. Non-conventional molecular dynamics simulation techniques are used, and new methodologies of simulation and data analysis are proposed in each study. First, we describe the mechanisms of ligand dissociation from the LBDs. The most important ligand dissociation pathway is obtained, and the structural interpretation for its relevance is elucidated. Next, studies on the selectivity of the TRb-selective ligands Triac and GC-1 are shown. For Triac, the crystallographic structures seem to be contradictory with the observed selectivity. The simulations provide an explanation for this apparent contradiction, and reveal that entropic factors are responsible for the observed selectivity. For GC-1, simulations and crystallographic structures jointly show that interaction between residues of the LBD are mostly responsible for the b-selectivity. Studies on the temperature-induced denaturation of TRs are then presented. These simulations have shown that the LBDs denaturate first by the unwinding of the helices. Expansion of the hydrophobic core occurs only as a second step. These results explain the strong stabilizing effect of Triac on the LBDs. Finally, the mechanisms of thermal diffusion (vibrational energy transfer) on the LBDs are presented. This study shows that there are three basic mechanisms of kinetic energy diffusion in proteins. Different residues have different contributions to kinetic energy dissipation. In the case of the LBDs of TRs, Arginines have particularly important roles. Residues that are important for heat diffusion are also functionally relevant. Therefore, the thermal diffusion mechanisms may be important for the stability of the LBDs by means of the dissipation of kinetic energy perturbations. / Doutorado / Físico-Química / Doutor em Ciências

A jararaca-ilhoa (Bothrops insularis) é uma serpente criticamente ameaçada, endêmica da Ilha da Queimada Grande (IQG), litoral sul de São Paulo. Com a sua população em declínio, foi estabelecido um programa de reprodução em cativeiro, porém o conhecimento da sua biologia reprodutiva ainda é incipiente. Até o momento considera-se essa espécie como sazonal, com período de espermatogênese e cópulas associado, ocorrendo do outono até início da primavera, porém não existem estudos a cerca da endocrinologia reprodutiva. O objetivo desse trabalho foi validar um método de avaliação hormonal não invasiva por meio das fezes e realizar o monitoramento dos metabólitos fecais de testosterona em conjunto com avaliação plasmática de testosterona. Ao longo de 36 meses foram coletadas 156 amostras de fezes e 30 amostras de sangue de oito machos cativos. As concentrações de metabólitos fecais de testosterona variaram entre 10,9 à 249,3 ng/g de fezes, enquanto as concentrações de testosterona plasmática variaram de 0,07 à 0,30 ng/mL de plasma. Não houve diferença significativa entre as concentrações plasmáticas de testosterona e de metabólitos fecais de testosterona ao longo do ano, apesar dos machos demonstrarem comportamento reprodutivo durante esse período. Os dados corroboram com outros estudos de estocagem espermática, qualidade seminal e volume gonadal, porém vão de encontro à resultados de histologia testicular. São discutidas a possibilidade da espécie ser assazonal ou desses resultados serem uma consequência das condições do cativeiro. Esse estudo contribui com a validação de um novo método de avaliação longitudinal de esteroides sexuais em B. insularis, com o conhecimento da biologia reprodutiva de serpentes tropicais e com a conservação de animais ameaçados de extinção / The golden lancehead pitviper (Bothrops insularis) is a critically endangered snake, endemic of the Queimada Grande Island, southeastern Brazil. With its declining population, a captive breeding program was established, but the knowledge of its reproductive biology is incipient. By the time this species is considered as seasonal, with spermatogenesis period and matting associated, occurring from autumn until early spring, but there are no studies about their reproductive endocrinology. The aim of this study was to validate a noninvasively hormonal evaluation method through feces and carry out the monitoring of androgens in conjunction with plasma testosterone evaluation. Over 36 months 156 stool samples and 30 blood samples were collected from eight captive males. The fecal androgen concentrations ranged from 10.9 to 249.3 ng / g of feces and the plasma testosterone concentrations ranged from 0.07 to 0.30 ng / mL of plasma. There was no significant difference between the concentrations of fecal androgens and plasma throughout the year, although the males had shown successfully reproductive behavior during this period. The data corroborate whith other studies of sperm storage, sperm quality and gonadal volume, but disagreeded of the results of testicular histology. We discuss the possibility of the species be assazonal or these results are a consequence of the captivity conditions. This study contributes to the validation of a new longitudinal evaluation method of sex steroids in B. insularis, with the knowledge of the reproductive biology of tropical snakes and the conservation of endangered animals

O objetivo deste trabalho foi avaliar de maneira detalhada e sistemática os perfis hormonais sanguíneos, fecais, urinários e salivares das progestinas e estrógenos durante o ciclo estral induzido de ovinos. Foram colhidas amostras diárias durante um período de 60 dias de sete fêmeas adultas (n=8) saudáveis e sexualmente maduras. Antes do início da fase de colheita das amostras, todos os animais foram submetidos ao protocolo de tratamento hormonal para indução e sincronização do cio durante dozes dias. O primeiro ciclo ovariano de cada animal desse experimento, detectado logo após a indução do cio foi descartado e seus valores não foram utilizados nas análises hormonais, pois poderiam estar sob o efeito dos hormônios exógenos. A concentração dos progestágenos foi determinada pelas técnicas analíticas de Radioimunoensaio (RIE) e Enzimaimunoensaio (EIE) e os estrógenos por RIE. Houve correlações entre as concentrações de progesterona medidas nas matrizes sérica e fecal, sérica e salivar, fecal e salivar (r=0,90, p<0,0001; r=0,90, p<0,0001; r=0,92, p<0,0001, respectivamente) durante os ciclos estrais observados (n=15). Obtivemos correlação (r=0,74, p<0,0001) entre as concentrações dos estrógenos quantificados nas matrizes sérica e fecal, mas não entre estas concentrações e aquelas medidas na matriz salivar. Não obtivemos nenhuma correlação entre as concentrações medidas na matriz urinária com as quantificadas nas outras matrizes para nenhum dos hormônios estudados. Obtivemos correlação entre as concentrações de progesterona medidas na matriz fecal pelos métodos de RIE e EIE (r=0,78, p<0,0001) e também na matriz salivar pelos dois métodos empregados (r=0,81, p<0,0001). Os resultados do presente experimento indicam que os imunoensaios utilizados podem ser utilizados para a avaliação das concentrações de progestágenos nas matrizes fecal e salivar durante o ciclo estral em ovinos. / The aim of the present work was evaluate the hormonal profiles of progestins and estrogens in blood, feces, urine and saliva during the induced estral cycle in ovine. Samples were collected daily a 60-day period from eight adult (n=8) cycling ewes. The animals were previously submitted to a protocol of estrus induction and synchronization for twelve days. In order to avoid the effect of exogenous hormones, the first cycle immediately after the synchronization was not considered for hormonal analysis. Progestagen concentrations were quantified by two analytical techniques, radioimmunoassay (RIA) and enzyme immunoassay (EIA). Estrogen concentrations were assessed by radioimmunoassay. Correlations in progesterone concentrations were found to be significant for serum and feces, serum and saliva and feces and saliva (r=0.90, p<0.0001; r=0.90, p<0.0001; r=0.92, p<0.0001, respectively) during the estrous cycles (n=15). Estrogen concentrations in the serum and feces were also positively correlated (r=0.74, p<0.0001). Salivary concentrations of estrogens were not correlated with fecal or serum concentrations of the same hormone. No correlation was found between urinary concentrations and concentrations found in other matrixes for both progestagens and estrogens. Concentrations of progestagens obtained using RIA and EIA were correlated on feces (r=0.78, p<0.0001) and saliva (r=0.81, p<0.0001). Results indicate that both immunoassays used in the present experiment can be used to evaluate progestagen concentrations on fecal and salivary matrixes during the estrous cycle of sheep.

Type 2 Diabetes Mellitus (T2DM) is a metabolic disorder characterized by chronic hyperglycemia, which develops as a consequence of peripheral insulin resistance and defective insulin secretion from pancreatic β-cells. A high calorie diet coupled with physical inactivity are known risk factors for the development of T2DM; however, these alone fail to account for the rapid rise of the disease. Recent attention has turned to the role of environmental pollutants in the development of metabolic diseases. PBDEs (polybrominated diphenyl ethers) are environmental pollutants that have been linked to the development of type 2 diabetes (T2D), however, the precise mechanisms are not clear. In particular, their direct effect on insulin secretion is unknown. In this study, we show that two PBDE congeners, BDE-47 and BDE-85, potentiate glucose-stimulated insulin secretion (GSIS) in INS-1 832/13 cells. This effect of BDE-47 and BDE-85 on GSIS was dependent on thyroid receptor (TR). Both BDE-47 and BDE-85 (10 μM) activated Akt during an acute exposure. The activation of Akt by BDE-47 and BDE-85 plays a role in their potentiation of GSIS, as pharmacological inhibition of PI3K, an upstream activator of Akt, significantly lowers GSIS compared to compounds alone. This study suggests that BDE-47 and BDE-85 directly act on pancreatic β-cells to stimulate GSIS, and that this effect is mediated by the thyroid receptor (TR) and Akt activation. This can cause the β-cells to oversecrete insulin, potentially leading to hyperinsulinemia, insulin resistance, and high blood glucose. In contrast to the potential diabetogenic effects of POPs, there are several naturally-derived compounds which accomplish just the opposite, exerting sensitizing effect on the peripheral tissues and sparing effect on β-cells. TQ, a natural occurring quinone and the main bioactive component of plant Nigella sativa, undergoes intracellular redox cycling and re-oxidizes NADH to NAD+. TQ administration (20 mg/kg/bw/day) to the Diet-Induced Obesity (DIO) mice reduced their diabetic phenotype by decreasing fasting blood glucose and fasting insulin levels, and improved glucose tolerance and insulin sensitivity as evaluated by oral glucose and insulin tolerance tests (OGTT and ITT). Furthermore, TQ decreased serum cholesterol levels and liver triglycerides, increased protein expression of phosphorylated Akt, decreased serum levels of inflammatory markers resistin and MCP-1, and decreased the NADH/NAD+ ratio. These changes were paralleled by an increase in phosphorylated SIRT-1 and AMPKα in liver and phosphorylated SIRT-1 in skeletal muscle. TQ also increased insulin sensitivity in insulin-resistant HepG2 cells via a SIRT-1-dependent mechanism These findings are consistent with the TQ-dependent re-oxidation of NADH to NAD+, which stimulates glucose and fatty acid oxidation and activation of SIRT-1-dependent pathways. Taken together, these results demonstrate that TQ ameliorates the diabetic phenotype in the DIO mouse model of type 2 diabetes.