Leptin, the product of the ob gene, has been shown to reduce fat mass, food intake, hyperglycemia, and hyperinsulinemia and to increase whole-body glucose disposal. However, it is unknown if leptin improves insulin action in skeletal muscle. Therefore, the purpose of this investigation was to determine if chronic leptin administration increases insulin-stimulated skeletal muscle glucose uptake and transport. Sixty-nine female Sprague-Dawley rats (240 to 250 g) were randomly assigned to one of three groups: (1) control, (2) pair-fed, and (3) leptin. All animals were subcutaneously implanted with miniosmotic pumps that delivered 0.5 mg leptin/kg/d to the leptin animals and vehicle to the control and pair-fed animals for 14 days. Following this 14-day period, all animals were subjected to hindlimb perfusion to determine the rates of skeletal muscle glucose uptake and 3-O-methyl-D-glucose (3-MG) transport under basal, submaximal (500 microU/mL), and maximal (10,000 microU/mL) insulin concentrations. Chronic leptin treatment significantly increased (P < .05) the rate of glucose uptake across the hindlimb by 27%, 32%, and 47% under basal, submaximal, and maximal insulin, respectively, compared with the control and pair-fed condition. However, when the submaximal rate of glucose uptake was expressed as a percentage of maximal insulin-stimulated glucose uptake, no differences existed among the groups, indicating that leptin treatment does not increase insulin sensitivity. Rates of 3-MG transport in the soleus, plantaris, and white and red portions of the gastrocnemius (WG and RG) were significantly increased (P < .05) in leptin animals under all perfusion conditions. 3-MG transport was not different between control and pair-fed animals. Collectively, these findings suggest that improvements in insulin-stimulated skeletal muscle glucose uptake and transport following chronic leptin treatment result from increased insulin responsiveness.
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http://dx.doi.org/10.1016/s0026-0495(99)90070-7 | DOI Listing |
Mol Cell Endocrinol
January 2025
Research Institute of Medical and Health Sciences, University of Sharjah, P.O. Box 27272, Sharjah, United Arab Emirates; College of Medicine, University of Sharjah, P.O. Box 27272, Sharjah United Arab Emirates.
Vitamin D (VD) has been implicated in regulating insulin secretion and pancreatic β-cell function. Yet, the underlying molecular mechanism of VD in glucose homeostasis is not fully understood. This study investigates the effect of VD in regulating insulin secretion and pancreatic β-cell function.
View Article and Find Full Text PDFCell Commun Signal
January 2025
Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA.
One hallmark of cancer is the upregulation and dependency on glucose metabolism to fuel macromolecule biosynthesis and rapid proliferation. Despite significant pre-clinical effort to exploit this pathway, additional mechanistic insights are necessary to prioritize the diversity of metabolic adaptations upon acute loss of glucose metabolism. Here, we investigated a potent small molecule inhibitor to Class I glucose transporters, KL-11743, using glycolytic leukemia cell lines and patient-based model systems.
View Article and Find Full Text PDFParkinsonism Relat Disord
January 2025
Department of Nuclear Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul National University College of Medicine, Seoul, Republic of Korea. Electronic address:
Introduction: In isolated REM sleep behavior disorder (iRBD), the evidence of cognitive impairment and co-existing amyloid pathology suggests that mild behavioral impairment (MBI) may be associated with disease progression. In this study, we investigated MBI and its association with cognitive function, brain amyloid load and glucose metabolism in iRBD patients to evaluate the utility of MBI as a predictive marker of disease progression.
Methods: Patients with iRBD underwent a neuropsychological evaluation, F-florbetaben (FBB) PET, and F-fluorodeoxyglucose (FDG) PET.
Br J Hosp Med (Lond)
January 2025
Department of Sports Arts, Hebei Sport University, Shijiazhuang, Hebei, China.
A novel exercise protocol for cardiac rehabilitation aerobic (CRA) has been developed by Hebei Sport University, demonstrating efficacy in patients with coronary heart disease (CHD). The objective of this study was to evaluate the impact of CRA on precise cardiac rehabilitation (CR) for CHD patients presenting with stable angina pectoris. The study cohort comprised patients with stable angina who were categorized into three groups: the CRA group (n = 35), the power bicycles (PB) group (n = 34), and the control group (n = 43).
View Article and Find Full Text PDFExp Physiol
January 2025
Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, UK.
In health, the liver is a metabolically flexible organ that plays a key role in regulating systemic lipid and glucose concentrations. There is a constant flux of fatty acids (FAs) to the liver from multiple sources, including adipose tissue, dietary, endogenously synthesized from non-lipid precursors, intrahepatic lipid droplets and recycling of triglyceride-rich remnants. Within the liver, FAs are used for triglyceride synthesis, which can be oxidized, stored or secreted in very low-density lipoproteins into the systemic circulation.
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