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- All Subjects: Genistein
- Creators: Sweazea, Karen
- Member of: Barrett, The Honors College Thesis/Creative Project Collection
- Resource Type: Text
Description
Birds have unusually high plasma glucose concentrations compared to mammals of similar size despite their high metabolic rate. While birds use lipids as their main source of energy, it is still unclear how and why they maintain high plasma glucose concentrations. To investigate a potential underlying mechanism, this study looks at the role of lipolysis in glucose homeostasis. The purpose of this study is to examine the effects of decreased glycerol availability (through inhibition of lipolysis) on plasma glucose concentrations in mourning doves. The hypothesis is that decreased availability of glycerol will result in decreased production of glucose through gluconeogenesis leading to reduced plasma glucose concentrations. In the morning of each experiment, mourning doves were collected at the Arizona State University Tempe campus, and randomized into either a control group (0.9% saline) or experimental group (acipimox, 50mg/kg BM). Blood samples were collected prior to treatment, and at 1, 2, and 3 hours post-treatment. At 3 hours, doves were euthanized, and tissue samples were collected for analysis. Acipimox treatment resulted in significant increases in blood glucose concentrations at 1 and 2 hours post- treatment as well as renal triglyceride concentrations at 3 hours post-treatment. Change in plasma free glycerol between 0h and 3h followed an increasing trend for the acipimox treated animals, and a decreasing trend in the saline treated animals. These results do not support the hypothesis that inhibition of lipolysis should decrease blood glycerol and blood glucose levels. Rather, the effects of acipimox in glucose homeostasis appear to differ significantly between birds and mammals suggesting differing mechanisms for glucose homeostasis.
ContributorsKouteib, Soukaina (Author) / Sweazea, Karen (Thesis director) / Deviche, Pierre (Committee member) / Chandler, Douglas (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
Morbid obesity is associated with cardiovascular and metabolic disorders. A major contributor to the pathogenesis of these diseases is impaired vasodilation resulting from elevated reactive oxygen species (ROS). This is because certain ROS such as superoxide are raised with obesity and scavenge the endogenous vasorelaxant nitric oxide, resulting in hypertension. The objective of this study was to measure the ability of genistein to quench superoxide in the vasculature of ob/ob mice, an animal model of obesity and type 2 diabetes. Genistein is an isoflavonic phytoestrogen naturally found in soy products. While genistein has documented antioxidant and anti-inflammatory properties, it is not known whether this protects the vasculature from oxidative stress. Genistein was hypothesized to reduce superoxide in arteries from female ob/ob mice. The superoxide indicator dihydroethidium (DHE) [2µL/mL HEPES buffer] was added to isolated aortae and mesenteric arteries from mice fed either a control (standard rodent chow containing 200-300 mg genistein/kg) or genistein-enriched (600mg genistein/kg rodent chow) diets for 4 weeks. Frozen tissues sections were collected onto glass microscope slides and examined using confocal microscopy. Contrary to the hypothesis, a diet containing twice the amount of genistein found in standard chow did not significantly reduce superoxide concentrations in aortae (p=0.287) or mesenteric arteries (p=0.352). Superoxide dismutase, an antioxidant enzyme that breaks down superoxide, was significantly upregulated in the genistein-enriched diet group (p=0.004), although this elevation did not promote the breakdown of superoxide. In addition, the inflammatory marker iNOS was not downregulated in the genistein-enriched diet group (p>0.05). The results indicate that high amounts of isoflavones, like genistein, may not exhibit the purported antioxidant effects in the vasculature of obese or diabetic subjects. Further studies examining arteries from ob/ob mice fed a genistein-free diet are needed to elucidate the true effects of genistein on oxidative stress.
ContributorsSimperova, Anna Marie (Co-author) / Al-Nakkash, Layla (Co-author) / Ricklefs, Kristin (Co-author) / Faust, James J. (Co-author) / Sweazea, Karen L. (Co-author) / Sweazea, Karen (Thesis director) / Gonzales, Rayna (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / T. Denny Sanford School of Social and Family Dynamics (Contributor)
Created2014-05
Description
As the 7th leading cause of death in the world, with over 1.6 millions deaths attributed to it in 2016 alone, diabetes mellitus has been a rising global health concern. Type 1 diabetes is caused by lack of insulin production whereas type 2 diabetes is caused by insulin resistance. Both types of diabetes lead to increased glucose levels in the body if left untreated. This, in turn, leads to the development of a host of complications, one of which is ischemic heart disease. Accounting for the death of 16% of the world’s population, ischemic heart disease has been the leading cause of death since 2000. As of 2019, deaths from this disease have risen from 2 million to over 8.9 million globally. While medicine exists to counter the negative outcomes of diabetes mellitus, lower income nations suffer from the lack of availability and high costs of these medications. Therefore, this systematic review was performed to determine whether a non-medicinal treatment could provide similar therapeutic benefits for individuals with diabetes. Genistein is a phytoestrogen found in soy-based products, which has been potentially linked with preventing diabetes and improving diabetes-related symptoms such as hyperglycemia and abnormal insulin levels. We searched PubMed and SCOPUS using the terms ‘genistein’, ‘diabetes’, and ‘glucose’ and identified 32 peer-reviewed articles. In general, preclinical studies demonstrate that genistein decreases body weight as well as circulating glucose and triglycerides concentrations while increasing insulin levels and insulin sensitivity. It also delayed the onset of type 1 and type 2 diabetes. In contrast, clinical studies of genistein in general reported no significant relationship between genistein and body mass, circulating glucose, serum insulin, A1C concentrations, or onset of type 1 diabetes. However, genistein was found to improve insulin sensitivity, delay type 2 diabetes onset and improve serum triglyceride levels. In summary, preclinical and clinical studies suggest that genistein may help delay onset of type 2 diabetes and improve several symptoms associated with the disease. By translating these findings into clinical settings, genistein may offer a cost effective natural approach at mitigating complications associated with diabetes, although additional research is required to confirm these findings.
ContributorsJain, Rijul (Author) / Sweazea, Karen (Thesis director) / Al-Nakkash, Layla (Committee member) / Bolch, Charlotte (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-04-16