Circulating branched-chain amino acid (BCAA) levels are elevated in obesity/diabetes and are a sensitive predictor for type 2 diabetes. Here we show in rats that insulin dose-dependently lowers plasma BCAA levels through induction of hepatic protein expression and activity of branched-chain α-keto acid dehydrogenase (BCKDH), the rate-limiting enzyme in the BCAA degradation pathway. Selective induction of hypothalamic insulin signaling in rats and genetic modulation of brain insulin receptors in mice demonstrate that brain insulin signaling is a major regulator of BCAA metabolism by inducing hepatic BCKDH. Short-term overfeeding impairs the ability of brain insulin to lower BCAAs in rats. High-fat feeding in nonhuman primates and obesity and/or diabetes in humans is associated with reduced BCKDH protein in liver. These findings support the concept that decreased hepatic BCKDH is a major cause of increased plasma BCAAs and that hypothalamic insulin resistance may account for impaired BCAA metabolism in obesity and diabetes.
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http://dx.doi.org/10.1016/j.cmet.2014.09.003 | DOI Listing |
Am J Physiol Cell Physiol
January 2025
School of Health and Exercise Sciences, The University of British Columbia, Okanagan,BC V1V 1V7, Canada.
People with type 2 diabetes (T2D) have a greater risk of developing neurodegenerative diseases, like Alzheimer's disease, in later life. Exogenous ketone supplements containing the ketone body β-hydroxybutyrate (β-OHB) may be a strategy to protect the brain as β-OHB can support cerebral metabolism and promote neuronal plasticity via expression of brain-derived neurotrophic factor (BDNF). Parallel human (ClinicalTrials.
View Article and Find Full Text PDFAm J Physiol Regul Integr Comp Physiol
December 2024
Curtin University, Curtin Medical Research Institute (Bentley, WA, AUSTRALIA).
Physical activity improves myocardial structure, function and resilience via complex, incompletely defined mechanisms. We explored effects of 1-2 wks swim training on cardiac and systemic phenotype in young male C57Bl/6 mice. Two wks forced swimming (90 min twice daily) resulted in cardiac hypertrophy (22% increase in heart:body weight, P<0.
View Article and Find Full Text PDFJ Alzheimers Dis
January 2025
Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China.
Background: Type 2 diabetes mellitus (T2D) and Alzheimer's disease (AD) are two prevalent chronic diseases that pose significant global health challenges. Increasing evidence suggests a complex bidirectional relationship between these conditions, where T2D elevates the risk of AD, and AD exacerbates glucose metabolism abnormalities in T2D.
Objective: This review explores the molecular mechanisms linking T2D and AD, focusing on the role of insulin signaling pathways and oxidative stress.
Brain Res Bull
January 2025
First Affiliated Hospital, Heilongjiang University of Chinese Medicine, Harbin, Heilongjiang 150040, China. Electronic address:
Major depressive disorder (MDD) is a common mental disorder with chronic tendencies that seriously affect regular work, life, and study. However, its exact pathogenesis remains unclear. Patients with MDD experience systemic and localized impairments in glucose metabolism throughout the disease course, disrupting various processes such as glucose uptake, glycoprotein transport, glycolysis, the tricarboxylic acid cycle (TCA), and oxidative phosphorylation (OXPHOS).
View Article and Find Full Text PDFImmun Inflamm Dis
January 2025
Department of Clinical Laboratory, Norinco General Hospital, Xi'an, Shaanxi, China.
Background: Recent studies show that N6-methyladenosine (m6A) plays an important role in the pathogenesis of the Alzheimer's disease (AD), while the mechanisms involved were studied insufficiently.
Aims: The present study aimed to explore the effect of human insulin-like growth factor 2 (IGF2) mRNA binding proteins 2 (IGF2BP2), one of the m6A-binding proteins on the progression of AD.
Materials & Methods: The mRNA and protein expression level were determined using RT-qPCR and western blot, respectively.
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