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Navakkode S, Kennedy BK. Neural ageing and synaptic plasticity: prioritizing brain health in healthy longevity. Front Aging Neurosci 2024; 16:1428244. [PMID: 39161341 PMCID: PMC11330810 DOI: 10.3389/fnagi.2024.1428244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Accepted: 07/24/2024] [Indexed: 08/21/2024] Open
Abstract
Ageing is characterized by a gradual decline in the efficiency of physiological functions and increased vulnerability to diseases. Ageing affects the entire body, including physical, mental, and social well-being, but its impact on the brain and cognition can have a particularly significant effect on an individual's overall quality of life. Therefore, enhancing lifespan and physical health in longevity studies will be incomplete if cognitive ageing is over looked. Promoting successful cognitive ageing encompasses the objectives of mitigating cognitive decline, as well as simultaneously enhancing brain function and cognitive reserve. Studies in both humans and animal models indicate that cognitive decline related to normal ageing and age-associated brain disorders are more likely linked to changes in synaptic connections that form the basis of learning and memory. This activity-dependent synaptic plasticity reorganises the structure and function of neurons not only to adapt to new environments, but also to remain robust and stable over time. Therefore, understanding the neural mechanisms that are responsible for age-related cognitive decline becomes increasingly important. In this review, we explore the multifaceted aspects of healthy brain ageing with emphasis on synaptic plasticity, its adaptive mechanisms and the various factors affecting the decline in cognitive functions during ageing. We will also explore the dynamic brain and neuroplasticity, and the role of lifestyle in shaping neuronal plasticity.
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Affiliation(s)
- Sheeja Navakkode
- Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, Centre for Healthy Longevity, National University Health System, National University of Singapore, Singapore, Singapore
- Life Sciences Institute Neurobiology Programme, Centre for Life Sciences, National University of Singapore, Singapore, Singapore
| | - Brian K. Kennedy
- Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, Centre for Healthy Longevity, National University Health System, National University of Singapore, Singapore, Singapore
- Life Sciences Institute Neurobiology Programme, Centre for Life Sciences, National University of Singapore, Singapore, Singapore
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Departments of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Buck Institute for Research on Ageing, Novato, CA, United States
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Yadav Y, Dey CS. Ser/Thr phosphatases: One of the key regulators of insulin signaling. Rev Endocr Metab Disord 2022; 23:905-917. [PMID: 35697962 DOI: 10.1007/s11154-022-09727-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/18/2022] [Indexed: 10/18/2022]
Abstract
Protein phosphorylation is an important post-translational modification that regulates several cellular processes including insulin signaling. The evidences so far have already portrayed the importance of balanced actions of kinases and phosphatases in regulating the insulin signaling cascade. Therefore, elucidating the role of both kinases and phosphatases are equally important. Unfortunately, the role of phosphatases is less studied as compared to kinases. Since brain responds to insulin and insulin signaling is reported to be crucial for many neuronal processes, it is important to understand the role of neuronal insulin signaling regulators. Ser/Thr phosphatases seem to play significant roles in regulating neuronal insulin signaling. Therefore, in this review, we discussed the involvement of Ser/Thr phosphatases in regulating insulin signaling and insulin resistance in neuronal system at the backdrop of the same phosphatases in peripheral insulin sensitive tissues.
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Affiliation(s)
- Yamini Yadav
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, New Delhi, 110016, India
| | - Chinmoy Sankar Dey
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, New Delhi, 110016, India.
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Salminen A, Kaarniranta K, Kauppinen A. Insulin/IGF-1 signaling promotes immunosuppression via the STAT3 pathway: impact on the aging process and age-related diseases. Inflamm Res 2021; 70:1043-1061. [PMID: 34476533 PMCID: PMC8572812 DOI: 10.1007/s00011-021-01498-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 08/24/2021] [Accepted: 08/26/2021] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The insulin/IGF-1 signaling pathway has a major role in the regulation of longevity both in Caenorhabditis elegans and mammalian species, i.e., reduced activity of this pathway extends lifespan, whereas increased activity accelerates the aging process. The insulin/IGF-1 pathway controls protein and energy metabolism as well as the proliferation and differentiation of insulin/IGF-1-responsive cells. Insulin/IGF-1 signaling also regulates the functions of the innate and adaptive immune systems. The purpose of this review was to elucidate whether insulin/IGF-1 signaling is linked to immunosuppressive STAT3 signaling which is known to promote the aging process. METHODS Original and review articles encompassing the connections between insulin/IGF-1 and STAT3 signaling were examined from major databases including Pubmed, Scopus, and Google Scholar. RESULTS The activation of insulin/IGF-1 receptors stimulates STAT3 signaling through the JAK and AKT-driven signaling pathways. STAT3 signaling is a major activator of immunosuppressive cells which are able to counteract the chronic low-grade inflammation associated with the aging process. However, the activation of STAT3 signaling stimulates a negative feedback response through the induction of SOCS factors which not only inhibit the activity of insulin/IGF-1 receptors but also that of many cytokine receptors. The inhibition of insulin/IGF-1 signaling evokes insulin resistance, a condition known to be increased with aging. STAT3 signaling also triggers the senescence of both non-immune and immune cells, especially through the activation of p53 signaling. CONCLUSIONS Given that cellular senescence, inflammaging, and counteracting immune suppression increase with aging, this might explain why excessive insulin/IGF-1 signaling promotes the aging process.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland.
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland
- Department of Ophthalmology, Kuopio University Hospital, KYS, P.O. Box 100, 70029, Kuopio, Finland
| | - Anu Kauppinen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland
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Akintola AA, van Heemst D. Insulin, aging, and the brain: mechanisms and implications. Front Endocrinol (Lausanne) 2015; 6:13. [PMID: 25705204 PMCID: PMC4319489 DOI: 10.3389/fendo.2015.00013] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 01/21/2015] [Indexed: 12/12/2022] Open
Abstract
There is now an impressive body of literature implicating insulin and insulin signaling in successful aging and longevity. New information from in vivo and in vitro studies concerning insulin and insulin receptors has extended our understanding of the physiological role of insulin in the brain. However, the relevance of these to aging and longevity remains to be elucidated. Here, we review advances in our understanding of the physiological role of insulin in the brain, how insulin gets into the brain, and its relevance to aging and longevity. Furthermore, we examine possible future therapeutic applications and implications of insulin in the context of available models of delayed and accelerated aging.
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Affiliation(s)
- Abimbola A. Akintola
- Department of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, Netherlands
- *Correspondence: Abimbola A. Akintola, Department of Gerontology and Geriatrics, Leiden University Medical Center, C7-124, Albinusdreef 2, Leiden 2333 ZA, Netherlands e-mail:
| | - Diana van Heemst
- Department of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, Netherlands
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Effect of chromium supplementation on the diabetes induced-oxidative stress in liver and brain of adult rats. Biometals 2011; 22:1075-87. [PMID: 19693677 DOI: 10.1007/s10534-009-9258-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2008] [Accepted: 07/30/2009] [Indexed: 10/20/2022]
Abstract
This study was designed to investigate the susceptibility of liver and brain tissues, as insulinin-dependent tissues, of normal adult male rats to the oxidative challenge of subchronic supplementation with chromium picolinate (CrPic) at low (human equivalent) and high doses (2.90 and 13.20 μg Cr kg(-1) day(-1), respectively). Also, the modulative effect of CrPic administration on the enhanced oxidative stress in the liver and brain tissues of alloxan-diabetic rats was studied. Fasting serum glucose level was not modified in normal rats but significantly reduced in diabetic rats that had received CrPic supplement. A mild oxidative stress was observed in the liver and brain of CrPic-supplemented normal rats confirmed by the dose-dependent reductions in the levels of hepatic and cerebral free fatty acids, superoxide dismutase and glutathione peroxidase activities, and in contrast increased tissue malondialdehyde concentration. On the other hand, hepatic and cerebral catalase activity was reduced in the high dose group only. CrPic supplementation did not act as a peroxisome proliferator confirmed by the significant reductions in liver and brain peroxisomal palmitoyl CoA oxidase activity. The non significant alterations in liver protein/DNA and RNA/DNA ratios indicate that CrPic did not affect protein synthesis per cell, and that mild elevations in hepatic total protein and RNA concentrations might be due to block or decrease in the export rate of synthesized proteins from the liver to the plasma. In diabetic rats, elevated levels of hepatic and cerebral free fatty acids and malondialdehyde, and in contrast the overwhelmed antioxidant enzymes, were significantly modulated in the low dose group and near-normalized in the high dose group. The significant increases observed in liver total protein and RNA concentrations, as well as protein/DNA and RNA/ DNA ratios in diabetic rats supplemented with the high dose of Cr, compared to untreated diabetics, may be related to the improvement in the glycemic status of the diabetic animals rather than the direct effect of CrPic on protein anabolism.
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Pielmeier U, Andreassen S, Nielsen BS, Chase JG, Haure P. A simulation model of insulin saturation and glucose balance for glycemic control in ICU patients. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2010; 97:211-222. [PMID: 19632735 DOI: 10.1016/j.cmpb.2009.06.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 06/05/2009] [Accepted: 06/09/2009] [Indexed: 05/28/2023]
Abstract
Consistent tight blood sugar control in critically ill patients has proven elusive. Properly accounting for the saturation of insulin action and reducing the need for frequent measurements are important aspects in intensive insulin therapy. This paper presents a composite metabolic model, 'Glucosafe', that integrates models and parameters from normal physiology and accounts for the reduced rate of glucose gut absorption and saturation of insulin action in patients with reduced insulin sensitivity. Particularly, two different sites of reduced insulin sensitivity, before and after the non-linearity of insulin action, are explored with this model. These approaches are assessed based on the model's accuracy in retrospectively predicting blood glucose measurements of 10 randomly chosen, hyperglycemic intensive care patients. For each patient, median absolute percent error is <25% for prediction times < or = 270min and modelling reduced insulin sensitivity after the non-linearity, compared to <29% for modelling reduced insulin sensitivity before the non-linearity. Scaling the insulin effect (after the non-linearity) is a suitable assumption in this model structure. These results are preliminary and subject to further and more extensive validation of the model's capability to predict the longer term (>2h) blood glucose excursion in critically ill patients.
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Affiliation(s)
- Ulrike Pielmeier
- Center for Model-based Medical Decision Support, Aalborg University, Fredrik-Bajers-Vej 7, E4-215, 9220 Aalborg, Denmark.
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Abstract
Gastric emptying is mildly slowed in healthy aging, although generally remains within the normal range for young people. The significance of this is unclear, but may potentially influence the absorption of certain drugs, especially when a rapid effect is desired. Type 2 diabetes is common in the elderly, but there is little data regarding its natural history, prognosis, and management. This article focuses on the interactions between gastric emptying and diabetes, how each is influenced by the process of aging, and the implications for patient management.
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Affiliation(s)
- Paul Kuo
- Discipline of Medicine, Royal Adelaide Hospital, North Terrace, Adelaide, South Australia 5000, Australia
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Korićanac G, Vulović M, Radivojsa S, Zakula Z, Ribarac-Stepić N. Age-related changes of insulin receptors, plasma insulin and glucose level. Biogerontology 2004; 5:345-53. [PMID: 15547322 DOI: 10.1007/s10522-004-2576-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The effects of aging on hepatic and erythrocyte insulin receptors have been investigated in 6, 12, 18 and 21-months-old compare to 3-months-old rats. Plasma insulin was elevated in 6, 12 and 18-months-old rats. Specific binding of insulin in liver was increased at the age of 8 months and accompanied with increase in concentration of low affinity binding sites, while specific binding to erythrocytes as well as concentration of both classes of binding sites was increased in 6-months-old rats. The protein and mRNA content of hepatic receptor were decreased only in the oldest animals. Plasma glucose was elevated starting from 12-months-old rats, while, after decrease in 6-months-old animals, citrulline was raised in the oldest group. The results demonstrating that specific binding of insulin in liver and erythrocytes and the concentration of binding sites in both tissues were not decreased during aging, as well as the absence of changes in affinity of insulin binding sites do not point out to occurrence of insulin resistance. However, the increase in insulinemia in the middle of lifespan, elevated plasma glucose and citrulline as well as decrease of hepatic receptor protein and mRNA content in the oldest animals indicate some age-related changes in insulin signaling.
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Affiliation(s)
- Goran Korićanac
- Department for Molecular Biology and Endocrinology, Vinca Institute of Nuclear Sciences, PO Box 522, 11001 Belgrade, Serbia and Montenegro.
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Meletis CD, Barker J. Natural Treatments for Metabolic Syndrome: Using Nutraceuticals to Thwart a Deadly Trend. ACTA ACUST UNITED AC 2003. [DOI: 10.1089/107628003322658548] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Fulop T, Larbi A, Douziech N. Roles of growth hormone and insulin-like growth factor 1 in mouse postnatal growth. Dev Biol 2001; 51:574-80. [PMID: 14622948 DOI: 10.1016/j.patbio.2003.09.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
To examine the relationship between growth hormone (GH) and insulin-like growth factor 1 (IGF1) in controlling postnatal growth, we performed a comparative analysis of dwarfing phenotypes manifested in mouse mutants lacking GH receptor, IGF1, or both. This genetic study has provided conclusive evidence demonstrating that GH and IGF1 promote postnatal growth by both independent and common functions, as the growth retardation of double Ghr/Igf1 nullizygotes is more severe than that observed with either class of single mutant. In fact, the body weight of these double-mutant mice is only approximately 17% of normal and, in absolute magnitude ( approximately 5 g), only twice that of the smallest known mammal. Thus, the growth control pathway in which the components of the GH/IGF1 signaling systems participate constitutes the major determinant of body size. To complement this conclusion mainly based on extensive growth curve analyses, we also present details concerning the involvement of the GH/IGF1 axis in linear growth derived by a developmental study of long bone ossification in the mutants.
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Affiliation(s)
- Tamas Fulop
- Centre de Recherche sur le vieillissement, Institut Universitaire de Gériatrie, Service de Gériatrie, Département de Médecine, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, Que., Canada J1H 4C4.
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Rubin MA, Miller JP, Ryan AS, Treuth MS, Patterson KY, Pratley RE, Hurley BF, Veillon C, Moser-Veillon PB, Anderson RA. Acute and chronic resistive exercise increase urinary chromium excretion in men as measured with an enriched chromium stable isotope. J Nutr 1998; 128:73-8. [PMID: 9430605 DOI: 10.1093/jn/128.1.73] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Both exercise and chromium exert beneficial effects on insulin function. The mechanism by which exercise improves insulin response may involve an alteration in Cr metabolism. To determine the effects of acute and chronic resistive exercise on urinary Cr losses, we measured the effects of acute resistive exercise and 16 wk of resistive exercise training on urinary Cr losses of 10 men 53-63 y of age. Subjects consumed diets in compliance with the American Heart Association Phase I diet with a Cr content of 30 +/- 4 microg/d. Sixteen weeks of resistive exercise training led to approximately 40% increases in upper and lower body strength, increases in fat-free mass and decreases in the percentage of body fat. An enriched stable isotope of Cr, 53Cr, was employed to differentiate the exogenously administered Cr from the native endogenous Cr. Both acute and chronic resistive exercise increased 53Cr losses. These data demonstrate that the improvements in body composition due to resistive exercise are associated with increased urinary Cr losses that are consistent with increased absorption.
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Affiliation(s)
- M A Rubin
- Department of Nutrition and Food Science, University of Maryland, College Park, MD 21218, USA
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Wang ZQ, Bell-Farrow AD, Sonntag W, Cefalu WT. Effect of age and caloric restriction on insulin receptor binding and glucose transporter levels in aging rats. Exp Gerontol 1997; 32:671-84. [PMID: 9785093 DOI: 10.1016/s0531-5565(97)00054-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We report on the effect of age and chronic caloric restriction (CR) on insulin binding and glucose transporter content in both diaphragm and heart muscle membrane of young (11 months), mid-age (17 months), and old (29 month) ad libitum fed and CR Brown-Norway rats. The control animals received rat chow ad lib and CR animals were allowed 60% of ad libitum food. The CR regimen was initiated at four months of age and the animals were maintained on their respective diets until necropsy. There was no effect of age on insulin binding for either ad libitum or CR animals at each age evaluated. Caloric restriction significantly lowered insulin levels at each age studied when compared to the ad libitum-fed rats. However, CR animals were noted to have increased insulin binding (p < 0.001) compared to ad libitum-fed animals at each age for diaphragm muscle. For the heart, there appeared to be a decreased binding, particularly at higher insulin concentrations, in CR-fed animals. There was no net change in Glut-1 or Glut-4 levels for heart muscle membrane, or Glut-4 levels for diaphragm muscle membrane between ad libitum or CR animals. This data indicates that caloric restriction may have tissue-specific effects for insulin receptor binding, and that the improved insulin sensitivity in CR states is not a result of altered glucose transporter protein content.
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Affiliation(s)
- Z Q Wang
- Department of Internal Medicine/Endocrinology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina 27157, USA
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Murray TM, Desai KS, Cinader B. Age-related changes in hepatic and splenic insulin receptors and serum insulin and glucose levels in inbred mice. Metabolism 1993; 42:140-4. [PMID: 8474309 DOI: 10.1016/0026-0495(93)90027-l] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Inbred mice of strains A/J, DBA/1J, and SJL/J were housed and aged in our animal colony, and parameters of carbohydrate metabolism were assessed at various ages. The patterns of age-related change were both organ- and strain-specific. Age-related changes in two of the strains were associated with relative carbohydrate intolerance. Common to all three strains was a biphasic pattern of change in hepatic insulin receptor number, with a decrease in early life and a return to earlier levels late in life. In both A/J and DBA/1J mice, there was a sharp increase in serum insulin level (twofold to 9.7-fold) that corresponded to the decrease in hepatic insulin receptors and was associated with hyperglycemia; no significant change in serum insulin or glucose levels was seen in SJL/J mice, despite a similar biphasic pattern in hepatic insulin receptor concentration. Age-related changes in splenic insulin receptors resembled changes in the liver in A/J and SJL/J mice, ie, there were synchronous biphasic age-related patterns. This was not the case in the spleens of DBA/1J mice, in which we did not observe age-related changes. There was no change in insulin receptor affinity with age, nor was there any difference in affinity between tissues or mouse strains. The pattern of change in hepatic insulin receptors and serum insulin levels was more complex than has been previously recognized. We do not know the mechanisms responsible for this complex pattern, but it must involve at least two discrete age-related events.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- T M Murray
- Division of Endocrinology and Metabolism, St. Michael's Hospital, Toronto, Ontario, Canada
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