Front Endocrinol (Lausanne)
November 2023
Forkhead box O (FoxO) proteins are transcription factors that mediate many aspects of physiology and thus have been targeted as therapeutics for several diseases including metabolic disorders such as type 2 diabetes mellitus (T2D). The role of FoxO1 in metabolism has been well studied, but recently FoxO1's potential for diabetes prevention and therapy has been debated. For example, studies have shown that increased FoxO1 activity in certain tissue types contributes to T2D pathology, symptoms, and comorbidities, yet in other tissue types elevated FoxO1 has been reported to alleviate symptoms associated with diabetes.
View Article and Find Full Text PDFJ Undergrad Neurosci Educ
December 2022
The Neuroscience Learning Community (LC) that Stonehill introduced to its curriculum grew out of the Great Recession of 2008 and the need for our students to gain hands-on, high-impact learning experiences, despite limited resources. This learning model was first reported in 2013, and since then it has undergone changes that were necessary due to the number of credits and amount of time required for that model. Curriculum changes are common, and Stonehill College changed its credit requirements for LCs to meet students' needs.
View Article and Find Full Text PDFJ Undergrad Neurosci Educ
November 2017
Skillful writing is essential for professionals in science and medicine. Consequently, many undergraduate institutions have adjusted their curriculum to include in-depth instruction and practice in writing for students majoring in the sciences. In neuroscience, students are often asked to write a laboratory report in the style of a primary scientific article or a term paper structured like a review article.
View Article and Find Full Text PDFUnderstanding the role of hypothalamic neuropeptides and hormones in energy balance is paramount in the search for approaches to mitigate the obese state. Increased hypothalamic-pituitary-adrenal axis activity leads to increased levels of glucocorticoids (GC) that are known to regulate body weight. The axis initiates the production and release of corticotropin-releasing hormone (CRH) from the paraventricular nucleus (PVN) of the hypothalamus.
View Article and Find Full Text PDFIn the periphery, the nutrient-sensing enzyme Sirtuin 1 (silent mating type information regulation 2 homolog 1 [Sirt1]) reduces body weight in diet-induced obese (DIO) rodents. However, the role of hypothalamic Sirt1 in body weight and energy balance regulation is debated. The first studies to reveal that central Sirt1 regulates body weight came from experiments in our laboratory using Sprague-Dawley rats.
View Article and Find Full Text PDFIn the periphery, the nutrient-sensing enzyme Sirtuin 1 (silent mating type information regulation 2 homolog 1 [Sirt1]) reduces body weight in diet-induced obese (DIO) rodents. However, the role of Sirt1 in the brain, particularly the hypothalamus, in body weight and energy balance regulation is debated. Among the first studies to reveal that central Sirt1 regulates body weight came from experiments in our laboratory using Sprague Dawley rats.
View Article and Find Full Text PDFPurpose: The purpose of this study was to define the information currently collected by state and territory Early Hearing Detection and Intervention (EHDI) coordinators and to determine whether best practice guidelines are used.
Method: A multiple-choice electronic survey querying areas of diagnostic assessment, amplification, early intervention (EI) and medical information regarding hearing loss was sent to all state and territory EHDI coordinators.
Results: Seventy percent of surveys were completed.
It was shown previously that abnormal prohormone processing or inactive proconverting enzymes that are responsible for this processing cause profound obesity. Our laboratory demonstrated earlier that in the diet-induced obesity (DIO) state, the appetite-suppressing neuropeptide α-melanocyte-stimulating hormone (α-MSH) is reduced, yet the mRNA of its precursor protein proopiomelanocortin (POMC) remained unaltered. It was also shown that the DIO condition promotes the development of endoplasmic reticulum (ER) stress and leptin resistance.
View Article and Find Full Text PDFAm J Physiol Endocrinol Metab
March 2013
Protein posttranslational processing is a cellular mechanism fundamental to the generation of bioactive peptides, including the anorectic α-melanocyte-stimulating hormone (α-MSH) and thyrotropin-releasing hormone (TRH) peptides produced in the hypothalamic arcuate (ARC) and paraventricular (PVN) nuclei, respectively. Neuropeptide Y (NPY) promotes positive energy balance in part by suppressing α-MSH and TRH. The mechanism by which NPY regulates α-MSH output, however, is not well understood.
View Article and Find Full Text PDFThimet oligopeptidase (TOP) and prolyl endopeptidase (PEP) are neuropeptidases involved in the hydrolysis of gonadotropin-releasing hormone, a key component of the hypothalamic-pituitary-gonadal axis. GnRH is regulated in part by feedback from steroid hormones such as estradiol. Previously, we demonstrated that TOP levels are down-regulated by estradiol in reproductively-relevant regions of the female rodent brain.
View Article and Find Full Text PDFThe neuropeptide thyrotropin releasing hormone (TRH) is necessary for adequate cold-induced thermogenesis. TRH increases body temperature via both neuroendocrine and autonomic mechanisms. TRH neurons of the hypothalamic paraventricular nucleus (PVN) regulate thermogenesis through the activation of the hypothalamic-pituitary-thyroid axis during cold exposure.
View Article and Find Full Text PDFProhormone convertases (PCs) 1 and 2 are the primary endoproteases involved in the post-translational processing of proThyrotropin Releasing Hormone (proTRH) to give rise to TRH and other proposed biologically active non-TRH peptides. Previous evidence suggests that PC1 is responsible for most proTRH cleavage events. Here, we used the PC1 and PC2 knockout (KO) mouse models to examine the effects of PC1 or PC2 loss on proTRH processing.
View Article and Find Full Text PDFComp Biochem Physiol A Mol Integr Physiol
November 2011
This study tested whether an ethologically relevant stressor, a three-week period of food restriction where food was unavailable for four hours a day, caused chronic stress in molting and non-molting captive European starlings. Although all birds increased weight during the Food Restriction period, only non-molting birds increased food intake. Morning baseline heart rates increased during the Food Restriction period and all birds showed a decrease in heart rate when food was absent from the cage.
View Article and Find Full Text PDFThe adipose tissue-derived hormone leptin regulates energy balance through catabolic effects on central circuits, including proopiomelanocortin (POMC) neurons. Leptin activation of POMC neurons increases thermogenesis and locomotor activity. Protein tyrosine phosphatase 1B (PTP1B) is an important negative regulator of leptin signaling.
View Article and Find Full Text PDFAm J Physiol Endocrinol Metab
December 2010
The hypothalamic-pituitary-thyroid (HPT) axis is a major contributor in maintaining energy expenditure and body weight, and the adipocyte hormone leptin regulates this axis by increasing TRH levels in the fed state. Leptin stimulates TRH directly in the hypothalamic paraventricular nucleus (PVN; direct pathway) and indirectly by regulating proopiomelnocortin neurons in the hypothalamic arcuate nucleus (ARC; indirect pathway). Whereas the indirect pathway is fully functional in lean animals, it is inactive during diet-induced obesity (DIO) because of the establishment of leptin resistance.
View Article and Find Full Text PDFIsland tameness is a widely documented phenomenon in which island species, particularly those that have evolved with no or few natural predators, show a greatly reduced behavioral response when faced with unfamiliar predators. This insufficient anti-predator response has led to widespread population declines among many island species exposed to novel predators, and has become a serious conservation problem. Despite its prevalence, the underlying physiology of island tameness is not known.
View Article and Find Full Text PDFHabituation is a term commonly used to explain a decrement in response intensity to a repeated stimulus or set of stimuli. In the stress literature, hormonal habituation is often used to describe a situation where an individual has learned to perceive a repeated stressor as innocuous, and thus the intensity of the release of hormonal stress mediators reduces over time. Consequently, a habituated individual is not considered stressed.
View Article and Find Full Text PDFThe cardiovascular-stress response has been studied extensively in laboratory animals but has been poorly studied in naturally selected species. We determined the relative roles of the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS) in regulating stress-induced changes in heart rate (HR) in wild-caught European starlings (Sturnus vulgaris). In both heart-rate variability (HRV) analysis and receptor blockade (atropine and propranolol) experiments, baseline HR was controlled predominantly by the PNS, whereas the increase in HR resulting from acute restraint stress was controlled predominantly by the SNS.
View Article and Find Full Text PDFFecal glucocorticoid metabolite (FGM) analysis has received considerable attention in conservation biology because it has potential to be used as a noninvasive measure of stress in animals. There has been a recent and extensive literature describing the importance of technical, physiological, and biological validations of this technique, yet surprisingly little is known about how FGM concentrations change during chronic stress. Therefore, we experimentally induced chronic stress in both captive and free-living European starlings (Sturnus vulgaris).
View Article and Find Full Text PDFPhysiol Biochem Zool
September 2008
Baseline and stress-induced corticosterone (CORT), heart rate (fH), and energy expenditure were measured in eight captive European starlings Sturnus vulgaris during and following a prebasic molt. The fH and oxygen consumption (V O2 ) were measured simultaneously across a range of heart rates, and energy expenditure (kJ/d) was then calculated from data. Energy expenditure and fH were strongly and positively correlated in each individual.
View Article and Find Full Text PDFAm J Physiol Regul Integr Comp Physiol
February 2008
We determined baseline and capture-induced glucocorticoid concentrations during two different seasons in three species of wild free-living rodents: brown lemmings (Lemmus trimucronatus), golden-mantled ground squirrels (Spermophilus saturatus), and yellow-pine chipmunks (Tamias amoenus). Initial blood samples were obtained within 3 min of capture, so that initial glucocorticoid levels reflect baseline titers of undisturbed animals. Animals were held for an additional 30 min, when a second blood sample was taken to measure stress-induced glucocorticoid titers.
View Article and Find Full Text PDFAlthough increases in glucocorticoid concentrations during acute stress are believed to help animals survive stressful events, chronic changes in glucocorticoid concentrations can alter metabolism and lead to disease. We studied the effect of chronic psychological stress on corticosterone (CORT), corticosterone binding globulin (CBG), glucose, and triglyceride concentrations as well as immune responsiveness to a T-cell mitogen challenge in European starlings, Sturnus vulgaris. To induce chronic stress we used a chronic stress protocol consisting of five stressors (loud radio, cage tapping, cage rolling, human voice, and bag restraint) administered in random order for 30 min for 4 times/day over 18 days.
View Article and Find Full Text PDFChronic increases in stress hormones such as glucocorticoids are maladaptive, yet studies demonstrating a causal relationship among chronic stress, increases in glucocorticoid concentrations, and subsequent fitness costs in free-living animals are lacking. We experimentally induced chronic psychological stress in female European starlings (Sturnus vulgaris) by subjecting half of the females at our study site to a chronic stress protocol consisting of 4, 30 min stressors (loud radio, predator calls, a novel object, or predator decoys including a snake, rat, and owl) administered in random order daily for 8 days after clutch completion. Experimental females were captured at the end of the chronic stress protocol (9 days after the onset of the chronic stress protocol), and unstressed control females were captured at the same stage of the nesting cycle.
View Article and Find Full Text PDFGen Comp Endocrinol
October 2006
Avian corticosterone (CORT) concentrations vary seasonally for many species, but most studies examined species from extreme environments or from only a few times of the year. It is unclear how general a phenomenon this is. We examined both baseline and stress-induced CORT from house sparrows (Passer domesticus) in two habitats-Massachusetts, similar to their ancestral habitat; and New Mexico, a semi-arid desert where the house sparrow only thrives as an obligate human commensal.
View Article and Find Full Text PDF