Endocrinology Commons^™

The Impact Of Growth Hormone-Releasing Hormone Antagonist On Human Adipose-Derived Stem Cells, Jeanne Michelle Dugas

Master's Theses

Obesity is a condition that affects over 40% of American adults and contributes to numerous preventable health issues. This condition is caused by increased adipose tissue, which forms when stem cells transform into adipocytes. Mesenchymal stem cells, including human adipose-derived stem cells (hASC), are multipotent with the ability to differentiate into adipocytes, osteocytes, or chondrocytes. Many factors affect this transformation, including the peptide growth hormone-releasing hormone (GHRH). The main role of GHRH is to trigger the release of growth hormone, but it has also been found to play an important role in adipocyte metabolism. We expect that if the differentiation …

Racial Health Disparities Among Pregnant Women Of Color In New York City: Biological And Systemic Impacts, Kaylin Peña

Pitzer Senior Theses

Racial Health Disparities Among Pregnant Women of Color in New York City: Biological and Systemic Impacts

Abstract

This thesis aims to explore how racial health disparities, underrepresentation in gynecology, and socioeconomic barriers contribute to adverse pregnancy outcomes among women of color in New York City. Through an interdisciplinary approach that combines resources from medical anthropology and human biology, this research will examine the biological implications of chronic stress, specifically HPA axis dysregulation, and its role in maternal health outcomes. With the idea of intersectionality, as conceptualized by Kimberlé Crenshaw, the study analyzes the various effects of systemic inequities and social …

Effect Of Glucocorticoid Blockade On Inflammatory Responses To Acute Sleep Fragmentation In Male Mice, Zim Hasan

Masters Theses & Specialist Projects

The association between sleep and the immune-endocrine system is well recognized, but the nature of that relationship is not well understood. Sleep fragmentation induces a pro-inflammatory response in peripheral tissues and brain, but it also activates the hypothalamic-pituitary-adrenal (HPA) axis, releasing glucocorticoids (GCs) (cortisol in humans and corticosterone in mice). It is unclear whether this rapid release of glucocorticoids acts to potentiate or dampen the inflammatory response in the short term. The purpose of this study was to determine whether blocking or suppressing glucocorticoid activity will affect the inflammatory response from acute sleep fragmentation (ASF). Male C57BL/6J mice were injected …

Estrogen Signaling Regulates The Sex Difference In Resynchronization To Abrupt Shifts Of The Light-Dark Cycle In A Mouse Model Of Jet Lag, Maria Venegas

Theses and Dissertations--Biology

The circadian system coordinates 24-hour cycles of internal biological processes with the environmental light-dark cycle. Abrupt shifts in the timing of the light-dark cycle misalign internal circadian clocks with the environment and cause jet lag until resynchronization occurs. The objective of this study was to investigate the mechanisms underlying sex differences in jet lag in mice. Female mice resynchronized faster than male mice to 6-hour advances and delays of the light-dark cycle, which mimicked eastward and westward travel, respectively. Circulating estradiol was necessary for rapid resynchronization in female mice since ovariectomized females resynchronized slower than mice treated with estradiol. We …

The Energetics Of Seasonality In Wild Diademed Sifaka (Propithecus Diadema): A Technical And Biological Validation Of Fecal Triiodothyronine Radioimmunassay, Casey Farmer

Graduate Research Theses & Dissertations

The energetic state of an animal has vital consequences for its fitness, but it can be difficult to detect through behavioral observations. The development of techniques to determine an animals’ energetic state non-invasively would allow conservation planners to rapidly assess the energy balance and conservation potential of individuals, groups, and populations. Thyroid hormones like triiodothyronine (T3) regulate and reflect metabolic state in mammals. T3 is a non-invasive biomarker that can be detected in feces and could potentially be used for this purpose. I perform the first validation of a commercially available T3 radioimmunoassay designed for humans on a wild strepsirrhine …

Microglial Response To Glucocorticoids During Chronic Sleep Fragmentation, Christian Chelson

Masters Theses & Specialist Projects

Sleep is one of the body’s greatest and most basic needs. Chronic sleep loss (<6 hours a day) is linked to many cardiovascular issues, diabetes, and inflammatory conditions and has been shown to lower life expectancy. Obstructive sleep apnea (OSA) is a complication that causes sleep fragmentation in >8% of adults from developed countries, and many with OSA may be unaware of their condition. Having long-term OSA is linked to neuroinflammation caused by activated microglia in the brain, but the mechanics of this inflammation are not well understood. It is known that glucocorticoids, steroid hormones produced and released from the adrenal glands, have a suppressive effect on microglia. The purpose of this study is to explore the role that glucocorticoids have upon microglia activation induced by chronic sleep fragmentation (SF). C57BL/6J mice were …

An Argument For The Utilization Of Amphibian Stress As An Indicator Of Wetland Condition, Andrew W. Sisson

Honors College Theses

Traditional forms of rapid wetland condition assessments focus on foliage health, nutrient enrichment, chemical contamination, and surrounding land usage, often overlooking an evaluation of the animals living in the wetland. More intense assessments include the National Wetland Condition Assessment (NWCA) and indices of biotic integrity, which focus on community composition (e.g., diversity and species richness) and abundances. These indices require expertise in species identification and do not provide information about the animal’s fitness. Animal stress physiology, which generally correlates with measures used to quantify animal fitness (e.g., survival, reproduction, and body condition), may provide a complementary rapid assessment method aimed …

Hormonal Control Of Osmoregulatory Proteins In The Intestine Of Atlantic Killifish (Fundulus Heteroclitus), Karma Hine

Biological Sciences Undergraduate Honors Theses

The Atlantic killifish (Fundulus heteroclitus) is a euryhaline fish, and thus able to maintain ionic and osmotic homeostasis in a wide range of salinities. When exposed to the dehydrating marine environment, the lost water is replenished through drinking seawater (SW) which is processed and absorbed in the intestine through the involvement of various cellular effectors. Intestinal water transport is osmotically driven by the active removal of NaCl from the gut lumen to the blood coupled to the precipitation of divalent Mg²⁺ and Ca²⁺ due to the secretion of bicarbonate. These processes allow for successive removal of …

Does Stress Physiology Mediate Disease Resistance In The Arizona Tiger Salamander (Ambystoma Mavortium Nebulosum)?, Megan Zerger

2023 Midwest Ecology & Evolution Conference

Amphibian biodiversity has greatly diminished in recent years due to disease. Panzootic pathogenic fungi Batrachochytrium dendrobatidis (Bd) causes the deadly disease chytridiomycosis (chytrid), a primary driver of catastrophic global amphibian declines and extinctions. The pathogenesis of chytrid is still unclear, as certain species and individuals within a species are differentially affected. Susceptibility and mortality of Bd are influenced by prolonged chronic stress. Prolonged glucocorticoid activity deleteriously affects many of the same physiological processes as Bd infections, and corticosterone is the primary glucocorticoid released by amphibians in response to stress. Thus, the objective of our study is to assess …

The Use Of A Habitat Quality Stress Index To Evaluate Stress As An Analog For Proximate Fitness In The American Crow Within A Matrix Of Landcover Characteristics To Assess Its Potential Contribution To Disease Etiologies, Theodore Lee Grabarz

Antioch University Dissertations & Theses

All organisms occur within spatial and temporal environments to maximize proximate fitness (health) and thus life history outcomes. Previous work has examined the temporal and behavioral aspects of proximate fitness on life history outcomes particularly regarding highly perturbed environments (i.e., climate and land use change, resource extraction, agricultural erosion, etc.). My work focuses on the less examined spatial aspect of these perturbed environments. More specifically, this dissertation examines habitat selection and quality as the basis for understanding stress response (negative and positive feedback mechanisms) to environmental stressors within the larger context of regional or gamma (ɣ) biodiversity. Through the lens …

Importance Of The Microhabitat And Microclimate Conditions In The Northern Gray-Cheeked Salamander (Plethodon Montanus) Across An Elevation Gradient, Trevor Chapman

Electronic Theses and Dissertations

The southern Appalachian Mountains have among the highest salamander diversity in the world, largely due to local speciation in the family Plethodontidae. Plethodontid salamanders (i.e., lungless salamanders) are particularly sensitive to habitat climate conditions due to their reliance on cutaneous respiration, and their immediate environmental conditions (microhabitat) likely influence their dispersion and activity more than the large-scale atmospheric conditions. The Northern Gray-cheeked salamander (Plethodon montanus) is restricted to high elevations in the Appalachian Mountains. Our goal was to investigate the relationship between P. montanus and its microhabitat by examining behavioral preference for climatic conditions, characterizing the microclimate with …

Effects Of Glucocorticoids Upon Pro-Inflammatory Responses To Acute Sleep Fragmentation, Hunter Weaver

Masters Theses & Specialist Projects

Sleep loss is a common problem in humans who suffer from obstructive sleep apnea. Sleep aids in the regulation of immune responses, some of which induce inflammatory responses. Cytokines regulate the inflammatory process and are released in response to sleep fragmentation (SF) in mice. Glucocorticoids are hormones that are released from the adrenal cortices during a stress response and are considered to be anti-inflammatory and immunosuppressive at high doses but may stimulate immune function on an acute level. The first hypothesis tested was that normal physiological expression of glucocorticoids (Sham) will display increased IL-1β and TNFα expression levels, while high …

Estrogen Regulation Of Daily Metabolic Rhythms In Female Mice, Oluwabukola Omotola

Theses and Dissertations--Biology

Circadian rhythms are approximately 24-hour cycles of behavior, physiology, and gene expression. In mammals, these circadian rhythms are generated by clocks located in nearly every tissue in the body. The function of circadian clocks is to synchronize physiology and behavior with environmental cycles such as the light-dark cycle. After menopause, when circulating levels of estrogens are very low, women are more susceptible to obesity comorbidities such as metabolic syndrome and cardiovascular disease, suggesting that estrogens regulate these processes. Estrogens could protect females from metabolic dysfunction by regulating circadian rhythms. Consumption of diets that are high in fat contribute to obesity. …

Effects Of Melatonin Implantation On The Activity Levels Of Captive Snow Buntings (Plectrophenax Nivalis), Zoë Ward

Mahurin Honors College Capstone Experience/Thesis Projects

In vertebrates, melatonin regulates many components of the circadian rhythm; depending on the organism’s location and time of year, the pineal gland will produce melatonin accordingly, controlling the sleep-wake cycle and breeding physiologies. However, locations at the poles in which the sun is above the horizon for multiple days at a time pose unique challenges for the organisms living there. The goal of this study was to examine how the implantation of melatonin in an arctic-breeding songbird affects its activity levels and circadian rhythm. The subject of this study, the snow bunting (Plectrophenax nivalis), is a small songbird …

Temperature-Induced Activation Of The Reproductive Axis Through Melatonin-Mediated Changes In Thyrotropin, Treven J. Winters

Dissertations and Theses

An animal's ability to synchronize life-history events or stages with optimal environmental conditions is paramount to successfully reproducing and maximizing fitness. Additional events including migration, foraging, rearing of young, and emergence from hibernation are all examples of processes under environmental control in one species or another. An exciting new mechanism involving neural thyroid hormone metabolism has been elucidated that links environmental control to the neuroendocrine reproductive axis. In birds and mammals with seasonal breeding cycles, this neuroendocrine pathway is activated by photoperiod-induced changes in thyroid stimulating hormone (TSH, also known as thyrotropin) production within the pars tuberalis region of the …

Morph- And Sex-Specific Differences In Corticosterone Of The Arizona Tiger Salamander (Ambystoma Mavortium Nebulosum), Megan Zerger

Scholars Week

Life history morph, sex, and body condition are traits that may influence stress within salamander populations because of differences in physiology and environmental conditions. Given widespread declines and the effects chronic stress can have on amphibian health, it is important to understand within-population drivers of stress and how population level variation may influence population viability. Thus, the objective of our study was to assess how corticosterone varies within the Arizona tiger salamander (Ambystoma mavortium nebulosum) population at the Mexican Cut Nature Preserve. We used a non-invasive skin swabbing method to collect baseline and elevated corticosterone from paedomorph (aquatic …

Effect Of Acute Sleep Fragmentation Upon Inflammatory Response Of Brown And White Adipose Tissue In Male Mice, Zach Wriedt

Mahurin Honors College Capstone Experience/Thesis Projects

Sleep is an important process required for vertebrates, including humans, to function. When sleep is disrupted, it leads to deleterious effects such as inflammatory responses throughout the body. Past studies have shown that acute (24 h) sleep fragmentation (SF) leads to an inflammatory response in white adipose tissue. However, whether brown adipose tissue responds in a similar fashion is unknown. Male adult (>8 weeks of age) C57BL/6j mice were subjected to SF for 24 h using a cage outfitted with a bar that moves horizontally across the cage every 2 min to periodically awaken mice (N =10). Controls were …

Monitoring Relationships Between Corticosterone And Snake Fungal Disease In Timber Rattlesnakes (Crotalus Horridus) In Western Kentucky, John Bromley Hewlett

Murray State Theses and Dissertations

Over the past four decades, emergent fungal diseases have been the most devastating relative to species declines and extinctions. While most research has focused on fungal diseases affecting amphibians and bats, less has focused on diseases like snake fungal disease (SFD), caused by Ophidiomyces ophiodiicola (Oo). SFD was first described in 2006 in North America within a Timber rattlesnake (Crotalus horridus) population in New Hampshire. Since then SFD has been documented in 19 US states, one US territory (Puerto Rico), and Europe. SFD causes high mortality in some species, including the Eastern Massasauga rattlesnakes (Sistrurus …

Estrogen Disruption Of Hypothalamic Neural Activity, Princess Dickson

Cal Poly Humboldt theses and projects

The brain is highly dependent on the endocrine system for proper neurodevelopment, as it plays a key role in many biological processes. Bisphenol A is a chemical found in plastics that has the potential to mimic the effects of Estrogen in the body, at least weakly. People interact with plastic that contains BPA regularly, and people are at risk for exposure even before being born. The abundance of BPA, along with other exogenous estrogens, makes examining the relationship between early exposure and changes in brain activity imperative. The current study aims to establish a relationship between disrupted estrogen function and …

The Effects Of Food Supply On Reproductive Hormones And Timing Of Reproduction In An Income-Breeding Seabird, Shannon Whelan, Scott A. Hatch, Z. Morgan Benowitz-Fredericks, Charline Parenteau, Olivier Chastel, Kyle Elliott

Faculty Journal Articles

Current food supply is a major driver of timing of breeding in income-breeding animals, likely because increased net energy balance directly increases reproductive hormones and advances breeding. In capital breeders, increased net energy balance increases energy reserves, which eventually leads to improved reproductive readiness and earlier breeding. To test the hypothesis that phenology of income-breeding birds is independent of energy reserves, we conducted an experiment on food-supplemented (“fed”) and control female black-legged kittiwakes (Rissa tridactyla). We temporarily increased energy costs (via weight handicap) in a 2 × 2 design (fed/unfed; handicapped/unhandicapped) during the pre-laying period and observed movement …

Influence Of Testosterone On Male-Male Competition In The Red-Sided Garter Snake, Thamnophis Sirtalis Parietalis, Isabella M. G. Bukovich

Senior Honors Projects, 2020-current

Female mimicry in the red-sided garter snake, Thamnophis sirtalis parietalis, is described in several well-studied evolutionary advantages, but an aspect that remains elusive is how reproductive traits are linked to the 3-fold higher circulating androgens in males with this phenotype. In this study, we implanted male garter snakes (n=15 per group) with either a blank implant (SHAM; control) or a T implant, the latter simulating the female mimic phenotype. Following simulated low-temperature dormancy, males were scored for courtship intensity over three days of behavioral trials with females housed in the same facility. Males were sacrificed, and sperm were collected …

Assessing Well-Being Of Asian Elephants (Elephas Maximus) Through Major Events And Transitions, With Development And Aging, And Husbandry Changes, Sharon Stuart Glaeser

Dissertations and Theses

In this body of research, reproductive and adrenal hormones and behavior were used to evaluate individual and group responses to physiological, social, and environmental changes in zoo-housed Asian elephants, considering factors of sex, age, and life stage. Animals experience physiological, social, and environmental changes as part of their natural history and individual life experience. Measures of both positive and negative states are needed to assess the impact of these changes at the individual and group level. Such measures can help us better understand how animals cope with a changing environment, and can help inform management decisions. Through longitudinal analyses of …

The Effect Of Intensified Illuminance And Artificial Light At Night On Fitness And Susceptibility To Abiotic And Biotic Stressors, Grascen Shidemantle

Biological Sciences Student Scholarship

Changing light conditions due to human activities represents an important emerging environmental concern. Although changes to natural light conditions can be independently detrimental, in nature, organisms commonly face multiple stressors. To understand the consequences of altered light conditions, we exposed a model amphibian (wood frog; Lithobates sylvaticus) to a control and two anthropogenic light conditions: intensified daytime illuminance and artificial light at night - ALAN (intensified daytime illuminance + extended photoperiod). We measured (1) metrics of fitness (hatching success as well as survival to, size at, and time to metamorphosis) (2) susceptibility (time to death) to a commonly cooccurring anthropogenic …

Impact Of Nacl Tolerance On The Stress Physiology And Fitness Of Larval Wood Frogs (Rana Sylvatica), Grascen Shidemantle, Nicholas Buss, Jessica Hua

Biological Sciences Student Scholarship

No abstract provided.

Prenatal Aromatase Inhibition Alters Postnatal Immunity In Domestic Chickens (Gallus Gallus), Jeff W. Simkins, Abby E. Joseph, Frances Bonier, Z. Morgan Benowitz-Fredericks

Faculty Journal Articles

In birds, exposure to exogenous testosterone during embryonic development can suppress measures of immune function; however, it is unclear whether these effects are due to direct or indirect action via aromatization. Estradiol (E2) is synthesized from testosterone by the enzyme aromatase, and this conversion is a necessary step in many signaling pathways that are ostensibly testosterone-dependent. Many lines of evidence in mammals indicate that E2 can affect immune function. We tested the hypothesis that some of the immunomodulatory effects observed in response to in ovo testosterone exposure in birds are mediated by conversion to E2 by aromatase, by using fadrozole …

Non-Invasive Method For Leptin Supplementation In Zebrafish (Danio Rerio), Regan Mcnamara

Williams Honors College, Honors Research Projects

I tested the hypothesis that recombinant leptin protein can be introduced to zebrafish in vivo through non-invasive soaking in a solution containing the protein. One way to study various molecules’ effects in vivo is through intraperitoneal or intracerebroventricular injections during the embryonic or larval stage, which is invasive, difficult to administer, and can have a high mortality rate. 48 hours post fertilization (hpf) zebrafish were soaked in a His-tagged recombinant leptin protein solution at 10 nM and 100 nM concentrations (produced by Genscript). After soaking, zebrafish larvae were washed extensively to remove all recombinant protein on their exterior before homogenization. …

Stress And Body Composition Of Juvenile Alligator Snapping Turtles (Macrochelys Temminckii), Brandon Scott Tappmeyer

Graduate Theses/Dissertations

The alligator snapping turtle (Macrochelys temminckii), is a species of conservation concern that is the subject of multiple head-start and reintroduction efforts across its range. In captive propagation programs, producing offspring that are in optimal physiological condition maximizes the likelihood of success after release. The purpose of my study was to compare stress and body composition between one free-ranging reintroduced population and two captive populations. The two captive populations were both housed in southern Oklahoma, but one group was reared indoors whereas the other inhabited outdoor ponds at a national fish hatchery. I used circulating glucocorticoid (corticosterone) concentrations as an …

Embryonic Lethality Of Cranial Neural Crest Deletion Of Cdc73, Lilia Shen

Honors Scholar Theses

Hyperparathyroidism-jaw tumor (HPT-JT) syndrome is a disease characterized by parathyroid tumors, renal cysts or tumors, uterine tumors, and ossifying jaw fibromas. The cause of this syndrome is linked to a tumor suppressor gene called Cdc73, which encodes the protein product parafibromin. The loss of proper expression of Cdc73/parafibromin is implicated in the development of the tumors typical of HPT-JT, although the exact mechanisms of tumorigenesis are unclear. In particular, not much is understood about the development of ossifying fibromas (OF) of the jaw in this syndrome. OF is a benign bone neoplasm that can affect the mandible and …

Population Health Of Spotted Salamanders (Ambystoma Maculatum) In Created Vernal Pools: An Integrative Approach, Alice R. Millikin

Graduate Theses, Dissertations, and Problem Reports (ETD)

Habitat creation is an important tool for conservation to counteract habitat loss and degradation. Vernal pools are susceptible to destruction due to limited detection, protection, and regulation. These wetlands provide fishless breeding habitat for many amphibian species including spotted salamanders (Ambystoma maculatum) in eastern North America. Determining whether created vernal pool habitat is successful is often determined by demographic data of colonizing populations. I suggest that hormone levels, population genetics, and disease prevalence can improve our understanding of population health in created habitat. The goal of this dissertation was to assess the health of spotted salamander larvae in …

Of Course, Humans Are Not Unique!, Bernard Wallner

Animal Sentience

This commentary focuses on the question of the uniqueness of humans in comparison to other species and on the false assumption that single arguments support logical conclusions. Comparative analysis of genetic data in humans and nonhuman primates regarding the dopaminergic system of the subcortical mesolimbic reward system highlights homologous traits shared and modified by the process of evolution. Such an analytical approach is more relevant than claims of uniqueness.