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Regulation of hepatic glucose production and AMPK by AICAR but not by metformin depends on drug uptake through the equilibrative nucleoside transporter 1 (ENT1)
AIM: Recently we have observed differences in the ability of metformin and AICAR to repress glucose production from hepatocytes using 8CPT‐cAMP. Previous results indicate that, in addition to activating protein kinase A, 8CPT‐modified cAMP analogues suppress the nitrobenzylthioinosine (NBMPR)‐sensit...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Blackwell Publishing Ltd
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6282725/ https://www.ncbi.nlm.nih.gov/pubmed/29962100 http://dx.doi.org/10.1111/dom.13455 |
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author | Logie, Lisa Lees, Zoe Allwood, J. William McDougall, Gordon Beall, Craig Rena, Graham |
author_facet | Logie, Lisa Lees, Zoe Allwood, J. William McDougall, Gordon Beall, Craig Rena, Graham |
author_sort | Logie, Lisa |
collection | PubMed |
description | AIM: Recently we have observed differences in the ability of metformin and AICAR to repress glucose production from hepatocytes using 8CPT‐cAMP. Previous results indicate that, in addition to activating protein kinase A, 8CPT‐modified cAMP analogues suppress the nitrobenzylthioinosine (NBMPR)‐sensitive equilibrative nucleoside transporter ENT1. We aimed to exploit 8CPT‐cAMP, 8CPT‐2‐Methyl‐O‐cAMP and NBMPR, which is highly selective for a high‐affinity binding‐site on ENT1, to investigate the role of ENT1 in the liver‐specific glucose‐lowering properties of AICAR and metformin. METHODS: Primary mouse hepatocytes were incubated with AICAR and metformin in combination with cAMP analogues, glucagon, forskolin and NBMPR. Hepatocyte glucose production (HGP) and AMPK signalling were measured, and a uridine uptake assay with supporting LC‐MS was used to investigate nucleoside depletion from medium by cells. RESULTS: AICAR and metformin increased AMPK pathway phosphorylation and decreased HGP induced by dibutyryl cAMP and glucagon. HGP was also induced by 8CPT‐cAMP, 8CPT‐2‐Methyl‐O‐cAMP and NBMPR; however, in each case this was resistant to suppression by AICAR but not by metformin. Cross‐validation of tracer and mass spectrometry studies indicates that 8CPT‐cAMP, 8CPT‐2‐Methyl‐O‐cAMP and NBMPR inhibited the effects of AICAR, at least in part, by impeding its uptake into hepatocytes. CONCLUSIONS: We report for the first time that suppression of ENT1 induces HGP. ENT1 inhibition also impedes uptake and the effects of AICAR, but not metformin, on HGP. Further investigation of nucleoside transport may illuminate a better understanding of how metformin and AICAR each regulate HGP. |
format | Online Article Text |
id | pubmed-6282725 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | Blackwell Publishing Ltd |
record_format | MEDLINE/PubMed |
spelling | pubmed-62827252018-12-11 Regulation of hepatic glucose production and AMPK by AICAR but not by metformin depends on drug uptake through the equilibrative nucleoside transporter 1 (ENT1) Logie, Lisa Lees, Zoe Allwood, J. William McDougall, Gordon Beall, Craig Rena, Graham Diabetes Obes Metab Original Articles AIM: Recently we have observed differences in the ability of metformin and AICAR to repress glucose production from hepatocytes using 8CPT‐cAMP. Previous results indicate that, in addition to activating protein kinase A, 8CPT‐modified cAMP analogues suppress the nitrobenzylthioinosine (NBMPR)‐sensitive equilibrative nucleoside transporter ENT1. We aimed to exploit 8CPT‐cAMP, 8CPT‐2‐Methyl‐O‐cAMP and NBMPR, which is highly selective for a high‐affinity binding‐site on ENT1, to investigate the role of ENT1 in the liver‐specific glucose‐lowering properties of AICAR and metformin. METHODS: Primary mouse hepatocytes were incubated with AICAR and metformin in combination with cAMP analogues, glucagon, forskolin and NBMPR. Hepatocyte glucose production (HGP) and AMPK signalling were measured, and a uridine uptake assay with supporting LC‐MS was used to investigate nucleoside depletion from medium by cells. RESULTS: AICAR and metformin increased AMPK pathway phosphorylation and decreased HGP induced by dibutyryl cAMP and glucagon. HGP was also induced by 8CPT‐cAMP, 8CPT‐2‐Methyl‐O‐cAMP and NBMPR; however, in each case this was resistant to suppression by AICAR but not by metformin. Cross‐validation of tracer and mass spectrometry studies indicates that 8CPT‐cAMP, 8CPT‐2‐Methyl‐O‐cAMP and NBMPR inhibited the effects of AICAR, at least in part, by impeding its uptake into hepatocytes. CONCLUSIONS: We report for the first time that suppression of ENT1 induces HGP. ENT1 inhibition also impedes uptake and the effects of AICAR, but not metformin, on HGP. Further investigation of nucleoside transport may illuminate a better understanding of how metformin and AICAR each regulate HGP. Blackwell Publishing Ltd 2018-08-02 2018-12 /pmc/articles/PMC6282725/ /pubmed/29962100 http://dx.doi.org/10.1111/dom.13455 Text en © 2018 The Authors. Diabetes, Obesity and Metabolism published by John Wiley & Sons Ltd. This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Original Articles Logie, Lisa Lees, Zoe Allwood, J. William McDougall, Gordon Beall, Craig Rena, Graham Regulation of hepatic glucose production and AMPK by AICAR but not by metformin depends on drug uptake through the equilibrative nucleoside transporter 1 (ENT1) |
title | Regulation of hepatic glucose production and AMPK by AICAR but not by metformin depends on drug uptake through the equilibrative nucleoside transporter 1 (ENT1) |
title_full | Regulation of hepatic glucose production and AMPK by AICAR but not by metformin depends on drug uptake through the equilibrative nucleoside transporter 1 (ENT1) |
title_fullStr | Regulation of hepatic glucose production and AMPK by AICAR but not by metformin depends on drug uptake through the equilibrative nucleoside transporter 1 (ENT1) |
title_full_unstemmed | Regulation of hepatic glucose production and AMPK by AICAR but not by metformin depends on drug uptake through the equilibrative nucleoside transporter 1 (ENT1) |
title_short | Regulation of hepatic glucose production and AMPK by AICAR but not by metformin depends on drug uptake through the equilibrative nucleoside transporter 1 (ENT1) |
title_sort | regulation of hepatic glucose production and ampk by aicar but not by metformin depends on drug uptake through the equilibrative nucleoside transporter 1 (ent1) |
topic | Original Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6282725/ https://www.ncbi.nlm.nih.gov/pubmed/29962100 http://dx.doi.org/10.1111/dom.13455 |
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