Insulin Controls Triacylglycerol Synthesis through Control of Glycerol Metabolism and Despite Increased Lipogenesis
Under normoxic conditions, adipocytes in primary culture convert huge amounts of glucose to lactate and glycerol. This “wasting„ of glucose may help to diminish hyperglycemia. Given the importance of insulin in the metabolism, we have studied how it affects adipocyte response to...
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doaj-f741e23ce75e494490611df101f1cb902020-11-24T21:58:18ZengMDPI AGNutrients2072-66432019-02-0111351310.3390/nu11030513nu11030513Insulin Controls Triacylglycerol Synthesis through Control of Glycerol Metabolism and Despite Increased LipogenesisAna Cecilia Ho-Palma0Pau Toro1Floriana Rotondo2María del Mar Romero3Marià Alemany4Xavier Remesar5José Antonio Fernández-López6Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, 08028 Barcelona, SpainDepartment of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, 08028 Barcelona, SpainDepartment of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, 08028 Barcelona, SpainDepartment of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, 08028 Barcelona, SpainDepartment of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, 08028 Barcelona, SpainDepartment of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, 08028 Barcelona, SpainDepartment of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, 08028 Barcelona, SpainUnder normoxic conditions, adipocytes in primary culture convert huge amounts of glucose to lactate and glycerol. This “wasting„ of glucose may help to diminish hyperglycemia. Given the importance of insulin in the metabolism, we have studied how it affects adipocyte response to varying glucose levels, and whether the high basal conversion of glucose to 3-carbon fragments is affected by insulin. Rat fat cells were incubated for 24 h in the presence or absence of 175 nM insulin and 3.5, 7, or 14 mM glucose; half of the wells contained <sup>14</sup>C-glucose. We analyzed glucose label fate, medium metabolites, and the expression of key genes controlling glucose and lipid metabolism. Insulin increased both glucose uptake and the flow of carbon through glycolysis and lipogenesis. Lactate excretion was related to medium glucose levels, which agrees with the purported role of disposing excess (circulating) glucose. When medium glucose was low, most basal glycerol came from lipolysis, but when glucose was high, release of glycerol via breakup of glycerol-3P was predominant. Although insulin promotes lipogenesis, it also limited the synthesis of glycerol-3P from glucose and its incorporation into acyl-glycerols. We assume that this is a mechanism of adipose tissue defense to avoid crippling fat accumulation which has not yet been described.https://www.mdpi.com/2072-6643/11/3/513glucoseinsulinlactateglyceroladipocyteslipogenesis |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Ana Cecilia Ho-Palma Pau Toro Floriana Rotondo María del Mar Romero Marià Alemany Xavier Remesar José Antonio Fernández-López |
spellingShingle |
Ana Cecilia Ho-Palma Pau Toro Floriana Rotondo María del Mar Romero Marià Alemany Xavier Remesar José Antonio Fernández-López Insulin Controls Triacylglycerol Synthesis through Control of Glycerol Metabolism and Despite Increased Lipogenesis Nutrients glucose insulin lactate glycerol adipocytes lipogenesis |
author_facet |
Ana Cecilia Ho-Palma Pau Toro Floriana Rotondo María del Mar Romero Marià Alemany Xavier Remesar José Antonio Fernández-López |
author_sort |
Ana Cecilia Ho-Palma |
title |
Insulin Controls Triacylglycerol Synthesis through Control of Glycerol Metabolism and Despite Increased Lipogenesis |
title_short |
Insulin Controls Triacylglycerol Synthesis through Control of Glycerol Metabolism and Despite Increased Lipogenesis |
title_full |
Insulin Controls Triacylglycerol Synthesis through Control of Glycerol Metabolism and Despite Increased Lipogenesis |
title_fullStr |
Insulin Controls Triacylglycerol Synthesis through Control of Glycerol Metabolism and Despite Increased Lipogenesis |
title_full_unstemmed |
Insulin Controls Triacylglycerol Synthesis through Control of Glycerol Metabolism and Despite Increased Lipogenesis |
title_sort |
insulin controls triacylglycerol synthesis through control of glycerol metabolism and despite increased lipogenesis |
publisher |
MDPI AG |
series |
Nutrients |
issn |
2072-6643 |
publishDate |
2019-02-01 |
description |
Under normoxic conditions, adipocytes in primary culture convert huge amounts of glucose to lactate and glycerol. This “wasting„ of glucose may help to diminish hyperglycemia. Given the importance of insulin in the metabolism, we have studied how it affects adipocyte response to varying glucose levels, and whether the high basal conversion of glucose to 3-carbon fragments is affected by insulin. Rat fat cells were incubated for 24 h in the presence or absence of 175 nM insulin and 3.5, 7, or 14 mM glucose; half of the wells contained <sup>14</sup>C-glucose. We analyzed glucose label fate, medium metabolites, and the expression of key genes controlling glucose and lipid metabolism. Insulin increased both glucose uptake and the flow of carbon through glycolysis and lipogenesis. Lactate excretion was related to medium glucose levels, which agrees with the purported role of disposing excess (circulating) glucose. When medium glucose was low, most basal glycerol came from lipolysis, but when glucose was high, release of glycerol via breakup of glycerol-3P was predominant. Although insulin promotes lipogenesis, it also limited the synthesis of glycerol-3P from glucose and its incorporation into acyl-glycerols. We assume that this is a mechanism of adipose tissue defense to avoid crippling fat accumulation which has not yet been described. |
topic |
glucose insulin lactate glycerol adipocytes lipogenesis |
url |
https://www.mdpi.com/2072-6643/11/3/513 |
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