The role of glucose, insulin and NEFA in regulating tissue triglyceride accumulation: Substrate cooperation in adipose tissue versus substrate competition in skeletal muscle.
Nutr Metab Cardiovasc Dis
; 27(11): 956-963, 2017 Nov.
Article
en En
| MEDLINE
| ID: mdl-28967595
ABSTRACT
BACKGROUND AND AIMS:
Metabolic factors initiating adipose tissue expansion and ectopic triglyceride accumulation are not completely understood. We aimed to investigate the independent role of circulating glucose, NEFA and insulin on glucose and NEFA uptake, and lipogenesis in skeletal muscle and subcutaneous adipose tissue (SCAT). METHODS ANDRESULTS:
Twenty-two pigs were stratified according to four protocols 1) and 2) low NEFA + high insulin ± high glucose (hyperinsulinaemia-hyperglycaemia or hyperinsulinaemia-euglycaemia), 3) high NEFA + low insulin (fasting), 4) low NEFA + low insulin (nicotinic acid). Positron emission tomography with [18F]fluoro-2-deoxyglucose and [11C]acetate, was combined with [14C]acetate and [U-13C]palmitate enrichment techniques to assess glucose and lipid metabolism. Hyperinsulinaemia increased glucose extraction, whilst hyperglycaemia enhanced glucose uptake in skeletal muscle and SCAT. In SCAT, during hyperglycaemia, elevated glucose uptake was accompanied by greater [U-13C]palmitate-TG enrichment compared to the other groups, and by a 39% increase in de novo lipogenesis (DNL) compared to baseline, consistent with a 70% increment in plasma lipogenic index. Conversely, in skeletal muscle, [U-13C]palmitate-TG enrichment was higher after prolonged fasting.CONCLUSIONS:
Our data show the necessary role of hyperglycaemia-hyperinsulinaemia vs euglycaemia-hyperinsulinaemia in promoting expansion of TG stores in SCAT, by the consensual elevation in plasma NEFA and glucose uptake and DNL. In contrast, skeletal muscle NEFA uptake for TG synthesis is primarily driven by circulating NEFA levels. These results suggest that a) prolonged fasting or dietary regimens enhancing lipolysis might promote muscle steatosis, and b) the control of glucose levels, in association with adequate energy balance, might contribute to weight loss.Palabras clave
Texto completo:
1
Base de datos:
MEDLINE
Asunto principal:
Triglicéridos
/
Glucemia
/
Músculo Esquelético
/
Grasa Subcutánea
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Lipogénesis
/
Ácidos Grasos no Esterificados
/
Insulina
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Nutr Metab Cardiovasc Dis
Asunto de la revista:
ANGIOLOGIA
/
CARDIOLOGIA
/
CIENCIAS DA NUTRICAO
/
METABOLISMO
Año:
2017
Tipo del documento:
Article
País de afiliación:
Italia