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Hypothalamic POMC Deficiency Improves Glucose Tolerance Despite Insulin Resistance by Increasing Glycosuria

Hypothalamic proopiomelanocortin (POMC) is essential for the physiological regulation of energy balance; however, its role in glucose homeostasis remains less clear. We show that hypothalamic arcuate nucleus (Arc)POMC-deficient mice, which develop severe obesity and insulin resistance, unexpectedly...

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Autores principales: Chhabra, Kavaljit H., Adams, Jessica M., Fagel, Brian, Lam, Daniel D., Qi, Nathan, Rubinstein, Marcelo, Low, Malcolm J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Diabetes Association 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4764146/
https://www.ncbi.nlm.nih.gov/pubmed/26467632
http://dx.doi.org/10.2337/db15-0804
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author Chhabra, Kavaljit H.
Adams, Jessica M.
Fagel, Brian
Lam, Daniel D.
Qi, Nathan
Rubinstein, Marcelo
Low, Malcolm J.
author_facet Chhabra, Kavaljit H.
Adams, Jessica M.
Fagel, Brian
Lam, Daniel D.
Qi, Nathan
Rubinstein, Marcelo
Low, Malcolm J.
author_sort Chhabra, Kavaljit H.
collection PubMed
description Hypothalamic proopiomelanocortin (POMC) is essential for the physiological regulation of energy balance; however, its role in glucose homeostasis remains less clear. We show that hypothalamic arcuate nucleus (Arc)POMC-deficient mice, which develop severe obesity and insulin resistance, unexpectedly exhibit improved glucose tolerance and remain protected from hyperglycemia. To explain these paradoxical phenotypes, we hypothesized that an insulin-independent pathway is responsible for the enhanced glucose tolerance. Indeed, the mutant mice demonstrated increased glucose effectiveness and exaggerated glycosuria relative to wild-type littermate controls at comparable blood glucose concentrations. Central administration of the melanocortin receptor agonist melanotan II in mutant mice reversed alterations in glucose tolerance and glycosuria, whereas, conversely, administration of the antagonist Agouti-related peptide (Agrp) to wild-type mice enhanced glucose tolerance. The glycosuria of ArcPOMC-deficient mice was due to decreased levels of renal GLUT 2 (rGLUT2) but not sodium–glucose cotransporter 2 and was associated with reduced renal catecholamine content. Epinephrine treatment abolished the genotype differences in glucose tolerance and rGLUT2 levels, suggesting that reduced renal sympathetic nervous system (SNS) activity is the underlying mechanism for the observed glycosuria and improved glucose tolerance in ArcPOMC-deficient mice. Therefore, the ArcPOMC-SNS-rGLUT2 axis is potentially an insulin-independent therapeutic target to control diabetes.
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spelling pubmed-47641462017-03-01 Hypothalamic POMC Deficiency Improves Glucose Tolerance Despite Insulin Resistance by Increasing Glycosuria Chhabra, Kavaljit H. Adams, Jessica M. Fagel, Brian Lam, Daniel D. Qi, Nathan Rubinstein, Marcelo Low, Malcolm J. Diabetes Obesity Studies Hypothalamic proopiomelanocortin (POMC) is essential for the physiological regulation of energy balance; however, its role in glucose homeostasis remains less clear. We show that hypothalamic arcuate nucleus (Arc)POMC-deficient mice, which develop severe obesity and insulin resistance, unexpectedly exhibit improved glucose tolerance and remain protected from hyperglycemia. To explain these paradoxical phenotypes, we hypothesized that an insulin-independent pathway is responsible for the enhanced glucose tolerance. Indeed, the mutant mice demonstrated increased glucose effectiveness and exaggerated glycosuria relative to wild-type littermate controls at comparable blood glucose concentrations. Central administration of the melanocortin receptor agonist melanotan II in mutant mice reversed alterations in glucose tolerance and glycosuria, whereas, conversely, administration of the antagonist Agouti-related peptide (Agrp) to wild-type mice enhanced glucose tolerance. The glycosuria of ArcPOMC-deficient mice was due to decreased levels of renal GLUT 2 (rGLUT2) but not sodium–glucose cotransporter 2 and was associated with reduced renal catecholamine content. Epinephrine treatment abolished the genotype differences in glucose tolerance and rGLUT2 levels, suggesting that reduced renal sympathetic nervous system (SNS) activity is the underlying mechanism for the observed glycosuria and improved glucose tolerance in ArcPOMC-deficient mice. Therefore, the ArcPOMC-SNS-rGLUT2 axis is potentially an insulin-independent therapeutic target to control diabetes. American Diabetes Association 2016-03 2015-10-14 /pmc/articles/PMC4764146/ /pubmed/26467632 http://dx.doi.org/10.2337/db15-0804 Text en © 2016 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.
spellingShingle Obesity Studies
Chhabra, Kavaljit H.
Adams, Jessica M.
Fagel, Brian
Lam, Daniel D.
Qi, Nathan
Rubinstein, Marcelo
Low, Malcolm J.
Hypothalamic POMC Deficiency Improves Glucose Tolerance Despite Insulin Resistance by Increasing Glycosuria
title Hypothalamic POMC Deficiency Improves Glucose Tolerance Despite Insulin Resistance by Increasing Glycosuria
title_full Hypothalamic POMC Deficiency Improves Glucose Tolerance Despite Insulin Resistance by Increasing Glycosuria
title_fullStr Hypothalamic POMC Deficiency Improves Glucose Tolerance Despite Insulin Resistance by Increasing Glycosuria
title_full_unstemmed Hypothalamic POMC Deficiency Improves Glucose Tolerance Despite Insulin Resistance by Increasing Glycosuria
title_short Hypothalamic POMC Deficiency Improves Glucose Tolerance Despite Insulin Resistance by Increasing Glycosuria
title_sort hypothalamic pomc deficiency improves glucose tolerance despite insulin resistance by increasing glycosuria
topic Obesity Studies
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4764146/
https://www.ncbi.nlm.nih.gov/pubmed/26467632
http://dx.doi.org/10.2337/db15-0804
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