n-3 polyunsaturated fatty acids (PUFA) can exert beneficial effects on glucose homeostasis, especially in obese rodents. Gut incretin hormones regulate glucose and lipid homeostasis, but their involvement in the above effects is not entirely clear. This study aims to assess the effects of chronic n-3 PUFA administration on the insulin and incretin responses in C57BL/6N obese male mice subjected to oral glucose tolerance test (oGTT) after 8 weeks of feeding a corn-oil-based high-fat diet (cHF). The weight gain and adiposity were partially reduced in mice fed cHF in which some of the corn oil was replaced with n-3 PUFA concentrate containing ∼60% DHA and EPA in a 3 : 1 ratio. In addition, these mice had improved glucose tolerance, which was consistent with an increased insulin response to oral glucose and plasma glucagon-like peptide-1 (GLP-1) levels. While the stimulatory effects of n-3 PUFA on GLP-1 levels could not be attributed to changes in intestinal or plasma dipeptidyl peptidase-4 activity, their beneficial effects on glucose tolerance were abolished when mice were pretreated with the GLP-1 receptor antagonist exendin 9-39. Moreover, chronic n-3 PUFA intake prevented the detrimental effects of cHF feeding on glucose-stimulated insulin secretion in the pancreatic islets. Collectively, our data suggest that n-3 PUFA may modulate postprandial glucose metabolism in obese mice through a GLP-1-based mechanism. The significance of these findings in terms of the effective DHA and EPA ratio of the n-3 PUFA concentrate as well as the effect of n-3 PUFA in humans requires further research.

• MeSH
• aplikace orální MeSH
• dieta s vysokým obsahem tuků MeSH
• glukagonu podobný peptid 1 metabolismus   MeSH
• glukózový toleranční test MeSH
• homeostáza MeSH
• inzulin metabolismus   MeSH
• krevní glukóza metabolismus   MeSH
• kyseliny mastné omega-3 aplikace a dávkování   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• přijímání potravy MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• glukagonu podobný peptid 1 MeSH
• inzulin MeSH
• krevní glukóza MeSH
• kyseliny mastné omega-3 MeSH

Omega-3 polyunsatuarted fatty acids (PUFA) are associated with hypolipidemic and anti-inflammatory effects. However, omega-3 PUFA, usually administered as triacylglycerols or ethyl esters, could also compromise glucose metabolism, especially in obese type 2 diabetics. Phospholipids represent an alternative source of omega-3 PUFA, but their impact on glucose homeostasis is poorly explored. Male C57BL/6N mice were fed for 8 weeks a corn oil-based high-fat diet (cHF) alone or cHF-based diets containing eicosapentaenoic acid and docosahexaenoic acid (~3%; wt/wt), admixed either as a concentrate of re-esterified triacylglycerols (ω3TG) or Krill oil containing mainly phospholipids (ω3PL). Lean controls were fed a low-fat diet. Insulin sensitivity (hyperinsulinemic-euglycemic clamps), parameters of glucose homeostasis, adipose tissue function, and plasma levels of N-acylethanolamines, monoacylglycerols and fatty acids were determined. Feeding cHF induced obesity and worsened (~4.3-fold) insulin sensitivity as determined by clamp. Insulin sensitivity was almost preserved in ω3PL but not ω3TG mice. Compared with cHF mice, endogenous glucose production was reduced to 47%, whereas whole-body and muscle glycogen synthesis increased ~3-fold in ω3PL mice that showed improved adipose tissue function and elevated plasma adiponectin levels. Besides eicosapentaenoic and docosapentaenoic acids, principal component analysis of plasma fatty acids identified palmitoleic acid (C16:1n-7) as the most discriminating analyte whose levels were increased in ω3PL mice and correlated negatively with the degree of cHF-induced glucose intolerance. While palmitoleic acid from Krill oil may help improve glucose homeostasis, our findings provide a general rationale for using omega-3 PUFA-containing phospholipids as nutritional supplements with potent insulin-sensitizing effects.

• Klíčová slova
• C57BL/6 mice, High-fat diet, Insulin resistance, Krill oil, Omega-3 PUFA, Palmitoleate,
• MeSH
• dieta s vysokým obsahem tuků MeSH
• fosfolipidy aplikace a dávkování   metabolismus   MeSH
• glukosa metabolismus   MeSH
• homeostáza * MeSH
• inzulinová rezistence MeSH
• kyseliny mastné mononenasycené krev   MeSH
• myši inbrední C57BL MeSH
• myši obézní MeSH
• myši MeSH
• oleje rostlin metabolismus   MeSH
• potravní doplňky MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fosfolipidy MeSH
• glukosa MeSH
• kyseliny mastné mononenasycené MeSH
• oleje rostlin MeSH
• palmitoleic acid MeSH Prohlížeč

n-3 polyunsaturated fatty acids (n-3 PUFA) might regulate metabolism by lowering endocannabinoid levels. We examined time-dependent changes in adipose tissue levels of endocannabinoids as well as in parameters of glucose homeostasis induced by n-3 PUFA in dietary-obese mice, and compared these results with the effect of n-3 PUFA intervention in type 2 diabetic (T2DM) subjects. Male C57BL/6J mice were fed for 8, 16 or 24 weeks a high-fat diet alone (cHF) or supplemented with n-3 PUFA (cHF + F). Overweight/obese, T2DM patients on metformin therapy were given for 24 weeks corn oil (Placebo; 5 g/day) or n-3 PUFA concentrate as above (Omega-3; 5 g/day). Endocannabinoids were measured by liquid chromatography-tandem mass-spectrometry. Compared to cHF-fed controls, the cHF + F mice consistently reduced 2-arachidonoylglycerol (up to ~2-fold at week 24) and anandamide (~2-fold) in adipose tissue, while the levels of endocannabinoid-related anti-inflammatory molecules N-eicosapentaenoyl ethanolamine (EPEA) and N-docosahexaenoyl ethanolamine (DHEA) increased more than ~10-fold and ~8-fold, respectively. At week 24, the cHF + F mice improved glucose tolerance and fasting blood glucose, the latter being positively correlated with adipose 2-arachidonoylglycerol levels only in obese cHF-fed controls, like fasting insulin and HOMA-IR. In the patients, n-3 PUFA failed to reduce 2-arachidonoylglycerol and anandamide levels in adipose tissue and serum, but they increased both adipose tissue and serum levels of EPEA and DHEA. In conclusion, the inability of n-3 PUFA to reduce adipose tissue and serum levels of classical endocannabinoids might contribute to a lack of beneficial effects of these lipids on glucose homeostasis in T2DM patients.

• Klíčová slova
• 2-AG, DHEA, High-fat diet, Obesity, Omega-3 PUFA,
• MeSH
• bílá tuková tkáň metabolismus   MeSH
• diabetes mellitus 2. typu krev   dietoterapie   metabolismus   MeSH
• dieta s vysokým obsahem tuků škodlivé účinky   MeSH
• dospělí MeSH
• endokanabinoidy krev   metabolismus   MeSH
• glukosa metabolismus   MeSH
• krevní glukóza MeSH
• kyseliny mastné omega-3 aplikace a dávkování   MeSH
• lidé středního věku MeSH
• lidé MeSH
• modely nemocí na zvířatech MeSH
• myši inbrední C57BL MeSH
• myši obézní MeSH
• myši MeSH
• obezita krev   dietoterapie   etiologie   metabolismus   MeSH
• potravní doplňky * MeSH
• randomizované kontrolované studie jako téma MeSH
• senioři MeSH
• tělesná hmotnost MeSH
• výsledek terapie MeSH
• zvířata MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• senioři MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• endokanabinoidy MeSH
• glukosa MeSH
• krevní glukóza MeSH
• kyseliny mastné omega-3 MeSH

Mixed results have been obtained regarding the level of insulin resistance induced by high-fat diets rich in saturated fatty acids (SFA) when compared to those enriched by polyunsaturated fatty acids (PUFA), and how metabolic effects of marine PUFA of n-3 series, i.e. docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), depend on dietary lipid background. Here we compared two high-fat diets, in which the major lipid constituent was based either on SFA in the form of pork lard (LHF diet) or PUFA of n-6 series (Omega-6) as corn oil (cHF diet). Both cHF and LHF parental diets were also supplemented with EPA+DHA (∼30 g/kg diet) to produce cHF+F and LHF+F diet, respectively. Male C57BL/6N mice were fed the experimental diets for 8 weeks. Insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamps in mice fed LHF and cHF diets, and then metabolic effects of cHF+F and LHF+F diets were assessed focusing on the liver and epididymal white adipose tissue (eWAT). Both LHF and cHF induced comparable weight gain and the level of insulin resistance, however LHF-fed mice showed increased hepatic steatosis associated with elevated activity of stearoyl-CoA desaturase-1 (SCD1), and lower plasma triacylglycerol levels when compared to cHF. Despite lowering hepatic SCD1 activity, which was concomitant with reduced hepatic steatosis reaching the level observed in cHF+F mice, LHF+F did not decrease adiposity and the weight of eWAT, and rather further impaired insulin sensitivity relative to cHF+F, that tended to improve it. In conclusion, high-fat diets containing as much as ∼35 weight% as lipids induce similar weight gain and impairment of insulin sensitivity irrespective whether they are based on SFA or Omega-6. Although the SFA-rich diet containing EPA+DHA efficiently reduced hepatic steatosis, it did so without a corresponding improvement in insulin sensitivity and in the absence of effect on adiposity.

• Klíčová slova
• Hepatic steatosis, Insulin resistance, Obesity, Omega-3 fatty acids, Stearoyl-CoA desaturase-1,
• MeSH
• dietní tuky * analýza   farmakologie   MeSH
• inzulinová rezistence * MeSH
• kukuřičný olej * analýza   farmakologie   MeSH
• kyseliny mastné omega-3 * analýza   farmakologie   MeSH
• kyseliny mastné omega-6 analýza   farmakologie   MeSH
• myši MeSH
• tuková tkáň metabolismus   MeSH
• ztučnělá játra * metabolismus   patologie   prevence a kontrola   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• dietní tuky * MeSH
• kukuřičný olej * MeSH
• kyseliny mastné omega-3 * MeSH
• kyseliny mastné omega-6 MeSH
• lard MeSH Prohlížeč