ALDH2 rs671 is associated with elevated FPG, reduced glucose clearance and hepatic insulin resistance in Japanese men

2021 ◽  
Author(s):  
Kageumi Takeno ◽  
Yoshifumi Tamura ◽  
Saori Kakehi ◽  
Hideyoshi Kaga ◽  
Ryuzo Kawamori ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Alcohol Consumption ◽  
Alcohol Intake ◽  
Fasting Glucose ◽  
Fat Distribution ◽  
Hepatic Insulin Resistance ◽  
Japanese Men ◽  
Hepatic Insulin Sensitivity ◽  
Glucose Clearance

Abstract Background A recent meta-analysis of genome-wide association studies data from East Asians identified acetaldehyde dehydrogenase 2 (ALDH2) rs671 as a susceptibility variant for type 2 diabetes in males. Methods We studied 94 non-obese, non-diabetic, Japanese men. Using a two-step hyperinsulinemic-euglycemic clamp, we evaluated insulin sensitivity in muscle and liver. Intrahepatic lipid and fat distribution were measured using 1H-magnetic resonance spectroscopy and magnetic resonance imaging, respectively. We divided the subjects into risk carrying group with ALDH2 rs671 G/G (n=53) and non-risk carrying group with ALDH2 rs671 G/A or A/A (n=41). Results The risk carrying group had significantly higher levels of alcohol consumption (18.4 (IQR, 10.4–48.9) vs. 12.1(IQR, 1.3–29.0) g/day; P=0.003), elevated fasting plasma glucose (FPG) (97.5±7.9 vs. 93.5±6.2 mg/dL; P=0.010), lower hepatic insulin sensitivity (61.7±20.5% vs.73.1±15.9%; P=0.003) and lower fasting glucose clearance (0.84±0.8 dL·m -2·min -1 vs. 0.87±0.09 dL·m -2·min -1; P=0.047) than the non-risk carrying group, while insulin resistance in muscle and body fat distribution were similar. The single linear correlation analysis revealed significant correlations between alcohol consumption and hepatic insulin sensitivity (r=-0.262, P=0.011), fasting glucose clearance (r=-0.370, P<0.001) or FPG (r=0.489, P<0.001). The multiple regression analysis revealed that both ALDH2 rs671 G/G genotype and alcohol consumption were significant independent correlates for hepatic insulin sensitivity, while only alcohol consumption was a significant independent correlate for fasting glucose clearance. Conclusion Our data suggested that high-alcohol-intake dependent and independent hepatic insulin resistance and reduced fasting glucose clearance due to high alcohol intake could be a relatively upstream metabolic abnormality in ALDH2 rs671 G/G carriers.

Impact of PPAR-α induction on glucose homoeostasis in alcohol-fed mice

2013 ◽  
Vol 125 (11) ◽  
pp. 501-511 ◽  
Author(s):  
Valérie Lebrun ◽  
Olivier Molendi-Coste ◽  
Nicolas Lanthier ◽  
Christine Sempoux ◽  
Patrice D. Cani ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Liver Disease ◽  
Insulin Sensitivity ◽  
Alcohol Consumption ◽  
Insulin Signalling ◽  
Liver Steatosis ◽  
Hepatic Insulin Resistance ◽  
Alcoholic Fatty Liver ◽  
Glucose Homoeostasis

Alcohol consumption is a major cause of liver disease. It also associates with increased cardiovascular risk and Type 2 diabetes. ALD (alcoholic liver disease) and NAFLD (non-alcoholic fatty liver disease) share pathological features, pathogenic mechanisms and pattern of disease progression. In NAFLD, steatosis, lipotoxicity and liver inflammation participate to hepatic insulin resistance. The aim of the present study was to verify the effect of alcohol on hepatic insulin sensitivity and to evaluate the role of alcohol-induced steatosis and inflammation on glucose homoeostasis. C57BL/6J mice were fed for 20 days a modified Lieber–DeCarli diet in which the alcohol concentration was gradually increased up to 35% of daily caloric intake. OH (alcohol liquid diet)-fed mice had liver steatosis and inflammatory infiltration. In addition, these mice developed insulin resistance in the liver, but not in muscles, as demonstrated by euglycaemic–hyperinsulinaemic clamp and analysis of the insulin signalling cascade. Treatment with the PPAR-α (peroxisome-proliferator-activated receptor-α) agonist Wy14,643 protected against OH-induced steatosis and KC (Kupffer cell) activation and almost abolished OH-induced insulin resistance. As KC activation may modulate insulin sensitivity, we repeated the clamp studies in mice depleted in KC to decipher the role of macrophages. Depletion of KC using liposomes-encapsuled clodronate in OH-fed mice failed both to improve hepatic steatosis and to restore insulin sensitivity as assessed by clamp. Our study shows that chronic alcohol consumption induces steatosis, KC activation and hepatic insulin resistance in mice. PPAR-α agonist treatment that prevents steatosis and dampens hepatic inflammation also prevents alcohol-induced hepatic insulin resistance. However, KC depletion has little impact on OH-induced metabolic disturbances.

Effect of liver fat on insulin clearance

2007 ◽  
Vol 293 (6) ◽  
pp. E1709-E1715 ◽  
Author(s):  
Anna Kotronen ◽  
Satu Vehkavaara ◽  
Anneli Seppälä-Lindroos ◽  
Robert Bergholm ◽  
Hannele Yki-Järvinen
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Fat Content ◽  
Insulin Clearance ◽  
Liver Fat ◽  
Hepatic Insulin Resistance ◽  
Model Assessment ◽  
Liver Fat Content ◽  
Hepatic Insulin Sensitivity ◽  
Impaired Insulin

A fatty liver is associated with fasting hyperinsulinemia, which could reflect either impaired insulin clearance or hepatic insulin action. We determined the effect of liver fat on insulin clearance and hepatic insulin sensitivity in 80 nondiabetic subjects [age 43 ± 1 yr, body mass index (BMI) 26.3 ± 0.5 kg/m2]. Insulin clearance and hepatic insulin resistance were measured by the euglycemic hyperinsulinemic (insulin infusion rate 0.3 mU·kg−1·min−1for 240 min) clamp technique combined with the infusion of [3-3H]glucose and liver fat by proton magnetic resonance spectroscopy. During hyperinsulinemia, both serum insulin concentrations and increments above basal remained ∼40% higher ( P < 0.0001) in the high (15.0 ± 1.5%) compared with the low (1.8 ± 0.2%) liver fat group, independent of age, sex, and BMI. Insulin clearance (ml·kg fat free mass−1·min−1) was inversely related to liver fat content ( r = −0.52, P < 0.0001), independent of age, sex, and BMI ( r = −0.37, P = 0.001). The variation in insulin clearance due to that in liver fat (range 0–41%) explained on the average 27% of the variation in fasting serum (fS)-insulin concentrations. The contribution of impaired insulin clearance to fS-insulin concentrations increased as a function of liver fat. This implies that indirect indexes of insulin sensitivity, such as homeostatic model assessment, overestimate insulin resistance in subjects with high liver fat content. Liver fat content correlated significantly with fS-insulin concentrations adjusted for insulin clearance ( r = 0.43, P < 0.0001) and with directly measured hepatic insulin sensitivity ( r = −0.40, P = 0.0002). We conclude that increased liver fat is associated with both impaired insulin clearance and hepatic insulin resistance. Hepatic insulin sensitivity associates with liver fat content, independent of insulin clearance.

159 EFFECTS OF EMBRYO TRANSFER IN A LARGER BREED ON POSTNATAL GROWTH AND GLUCOSE METABOLISM IN HORSES

2013 ◽  
Vol 25 (1) ◽  
pp. 228
Author(s):  
P. Peugnet ◽  
A. Tarrade ◽  
C. Sandersen ◽  
M. Dahirel ◽  
D. Guillaume ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Embryo Transfer ◽  
Fetal Growth ◽  
Fasting Glucose ◽  
Plasma Concentrations ◽  
Postnatal Growth ◽  
Glucose Regulation ◽  
Intravenous Glucose ◽  
Glucose Clearance

In equids, the size of the uterus determines fetal intrauterine development, which in turn affects postnatal insulin sensitivity and growth rate. We induced intrauterine growth enhancement through embryo transfer using Pony (P), Saddlebred (S), and Draft (D) horses and studied growth and insulin sensitivity in foals from birth to one year of age. Control pregnancies of S-in-S (n = 14) and P-in-P (n = 10) were obtained by AI. Enhanced fetal growth was obtained by transferring S (S-in-D, n = 7) and P embryos (P-in-D, n = 5) into D mares. From birth to weaning (180 days), each foal was kept with its surrogate P, S, or D dam. At 3, 140, and 380 days, glucose clearance and pancreatic beta cell response to exogenous glucose were assessed with an intravenous glucose tolerance test (IVGTT). At 200 days, the euglycemic-hyperinsulinemic clamp method was used to determine the sensitivity and responsiveness of tissues to exogenous insulin. Plasma T3, T4, and IGF1 were assayed at 3 and 180 days. Data were analysed using one-way ANOVA and Tukey post hoc tests. S-in-S were heavier and taller than P-in-P from birth to 380 days (P < 0.001). Before weaning, plasma concentrations of several hormones involved in growth were lower in S-in-S than P-in-P (at 3 and 180 days, respectively, T3: P = 0.08 and P = 0.02, T4: P < 0.001 and P = 0.06, IGF1: P = 0.04 and P < 0.001). No difference was found in glucose regulation between these groups. In contrast, post-weaning insulin resistance was observed in P-in-P at 200 days (P < 0.001) and confirmed at 380 days where they exhibited slower glucose clearance (P = 0.03) associated with higher fasting glucose (P < 0.001) than S-in-S. Fetal growth was not enhanced in S-in-D with no difference in height and weight at birth. Although S-in-D grew faster from 30 to 140 days, growth rates were not different from S-in-S after weaning, weaning coinciding with lower T3 (P < 0.001) in S-in-D than in S-in-S. Glucose regulation was not different between the two groups, but insulin remains to be assayed at 140 and 380 days. Fetal growth was enhanced in P-in-D: at birth, they were heavier (P = 0.01) and taller (P < 0.001) than P-in-P. Growth of P-in-D was faster until weaning. No more difference, however, was observed between P-in-D and P-in-P at 380 days. Plasma concentrations of T3 (P = 0.03) and those of T4 (P < 0.001) were lower at 3 days and T3 was still lower at 180 days (P < 0.001) in P-in-D compared with P-in-P. Moreover, P-in-D developed early insulin resistance: insulin secretion was higher in P-in-D compared with P-in-P (P = 0.002) after IVGTT at 3 days. At 200 days, however, P-in-D and P-in-P had the same sensitivity to insulin. There was no difference in glucose clearance rates at 380 days, but P-in-D had lower fasting glucose (P < 0.001) than P-in-P. Insulin assays at 140 and 380 days are pending. In conclusion, these data indicate that transfer of a small breed embryo into a large breed mare and subsequent suckling by the recipient mare can enhance fetal and postnatal growth and affect the foal’s glycaemia and sensitivity to insulin at birth and in subsequent months. Ongoing work includes analyses of milk samples and effects on general health.

Accretion of visceral fat and hepatic insulin resistance in pregnant rats

2008 ◽  
Vol 294 (2) ◽  
pp. E451-E455 ◽  
Author(s):  
Francine H. Einstein ◽  
Sigal Fishman ◽  
Radhika H. Muzumdar ◽  
Xiao Man Yang ◽  
Gil Atzmon ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Visceral Fat ◽  
Hepatic Glucose Production ◽  
Late Gestation ◽  
Hepatic Insulin Resistance ◽  
Sprague Dawley ◽  
Pregnant Rats ◽  
Hepatic Insulin Sensitivity ◽  
In Pregnancy

Insulin resistance (IR) is a hallmark of pregnancy. Because increased visceral fat (VF) is associated with IR in nonpregnant states, we reasoned that fat accretion might be important in the development of IR during pregnancy. To determine whether VF depots increase in pregnancy and whether VF contributes to IR, we studied three groups of 6-mo-old female Sprague-Dawley rats: 1) nonpregnant sham-operated rats (Nonpreg; n = 6), 2) pregnant sham-operated rats (Preg; n = 6), and 3) pregnant rats in which VF was surgically removed 1 mo before mating (PVF−; n = 6). VF doubled by day 19 of pregnancy (Nonpreg 5.1 ± 0.3, Preg 10.0 ± 1.0 g, P < 0.01), and PVF− had similar amounts of VF compared with Nonpreg (PVF− 4.6 ± 0.8 g). Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp in late gestation in chronically catheterized unstressed rats. Glucose IR (mg·kg−1·min−1) was highest in Nonpreg (19.4 ± 2.0), lowest in Preg (11.1 ± 1.4), and intermediate in PVF− (14.7 ± 0.6; P < 0.001 between all groups). During the clamp, Nonpreg had greater hepatic insulin sensitivity than Preg [hepatic glucose production (HGP): Nonpreg 4.5 ± 1.3, Preg 9.3 ± 0.5 mg·kg−1·min−1; P < 0.001]. With decreased VF, hepatic insulin sensitivity was similar to nonpregnant levels in PVF− (HGP 4.9 ± 0.8 mg·kg−1·min−1). Both pregnant groups had lower peripheral glucose uptake compared with Nonpreg. In parallel with hepatic insulin sensitivity, hepatic triglyceride content was increased in pregnancy (Nonpreg 1.9 ± 0.4 vs. Preg 3.2 ± 0.3 mg/g) and decreased with removal of VF (PVF− 1.3 ± 0.4 mg/g; P < 0.05). Accretion of visceral fat is an important component in the development of hepatic IR in pregnancy, and accumulation of hepatic triglycerides is a mechanism by which visceral fat may modulate insulin action in pregnancy.

scholarly journals SUN-LB103 The Relationship Between Alcohol Consumption Patterns and Insulin Sensitivity in Obesity

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Katrina Han ◽  
Dominic Nicholas Reeds ◽  
Julia Passyn Dunn
Keyword(s):  
Insulin Resistance ◽  
Native American ◽  
Insulin Sensitivity ◽  
Alcohol Consumption ◽  
Binge Drinking ◽  
Alcohol Intake ◽  
Alcohol Exposure ◽  
P Value ◽  
Model Assessment ◽  
The Relationship

Abstract BACKGROUNDThe effects of alcohol intake on insulin sensitivity have produced conflicting results with both beneficial and adverse effects observed. This study aimed to compare the relationship between patterns of alcohol consumption and insulin sensitivity in obese Veterans. METHODSWe performed a cross-sectional study of obese (BMI 30.0-45.0 kg/m2), nondiabetic U.S. Military Veterans without active mental health diagnoses, including no report of dependent alcohol use within the last 12 months. Alcohol exposure over the previous 12 months (mos) was assessed using a study-developed questionnaire and Michigan Alcoholism Screening Test (MAST). Fasting insulin, glucose, and a 75gm OGTT were completed to determine Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) and prediabetes (preDM) score of 0, 1, or 2 based on fulfilling 0, 1, or at least 2 of the ADA criteria for preDM, respectively. Linear regression was used to assess for associations between measures of insulin resistance and alcohol consumption; unstandardized β and p-value are reported for variable of interest. RESULTS104 Veterans participated (66% males; 44±8years (range: 25-60); BMI 36±4kg/m2 (range: 29-45); 53% White, 46% African American, 2% Alaskan/Native American, 1% Other). 83 participants reported any alcohol intake in the previous 12 mos and neither preDM score (p=0.57) nor HOMA-IR (p=0.14) were predicted by this question. PreDM score groups were similar in gender, BMI, and weight, but age predicted both preDM score (r2=0.09, β=0.025, p=0.006) and HOMA-IR (r2=0.05, β=-0.09, p=0.034); therefore, all regressions were adjusted for age. There was a negative association between the number of days of alcohol intake with HOMA-IR (β=-0.271, p=0.037) but no association occurred with preDM score (p=0.15). Fewer days of binge drinking was associated with higher HOMA-IR (β= -0.342, p=0.058) and preDM score (β=-0.075, p=0.05). There was no significant association between total quantity of alcohol intake and HOMA-IR (p=0.13) nor preDM score (p=0.15). There was no association between MAST score and HOMA-IR (p=0.7) or preDM score (p=0.3). CONCLUSIONIn our cohort of obese, non-alcohol dependent Veterans, the reported number of days of alcohol intake and days of binge drinking in the previous 12 mos were lower in those with markers of insulin resistance. These results suggest that drinking patterns among obese patients may have unique effects on insulin sensitivity that warrant further investigation.

scholarly journals Short-Term Strength Exercise Reduces Hepatic Insulin Resistance in Obese Mice by Reducing PTP1B Content, Regardless of Changes in Body Weight

2021 ◽  
Vol 22 (12) ◽  
pp. 6402
Author(s):  
Kellen Cristina da Cruz Rodrigues ◽  
Rodrigo Martins Pereira ◽  
Guilherme Francisco Peruca ◽  
Lucas Wesley Torres Barbosa ◽  
Marcella Ramos Sant’Ana ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Body Weight ◽  
Insulin Sensitivity ◽  
Hepatic Insulin Resistance ◽  
Strength Exercise ◽  
Term Strength ◽  
Obese Mice ◽  
Short Term ◽  
Hepatic Insulin Sensitivity ◽  
Short Term Strength

Obesity is closely related to insulin resistance and type 2 diabetes genesis. The liver is a key organ to glucose homeostasis since insulin resistance in this organ increases hepatic glucose production (HGP) and fasting hyperglycemia. The protein-tyrosine phosphatase 1B (PTP1B) may dephosphorylate the IR and IRS, contributing to insulin resistance in this organ. Aerobic exercise is a great strategy to increase insulin action in the liver by reducing the PTP1B content. In contrast, no study has shown the direct effects of strength training on the hepatic metabolism of PTP1B. Therefore, this study aims to investigate the effects of short-term strength exercise (STSE) on hepatic insulin sensitivity and PTP1B content in obese mice, regardless of body weight change. To achieve this goal, obese Swiss mice were submitted to a strength exercise protocol lasting 15 days. The results showed that STSE increased Akt phosphorylation in the liver and enhanced the control of HGP during the pyruvate tolerance test. Furthermore, sedentary obese animals increased PTP1B content and decreased IRS-1/2 tyrosine phosphorylation; however, STSE was able to reverse this scenario. Therefore, we conclude that STSE is an important strategy to improve the hepatic insulin sensitivity and HGP by reducing the PTP1B content in the liver of obese mice, regardless of changes in body weight.

Starch and β-glucan in a whole-grain-like structural form improve hepatic insulin sensitivity in diet-induced obese mice

2019 ◽  
Vol 10 (8) ◽  
pp. 5091-5101 ◽  
Author(s):  
Kaiyun Luo ◽  
Xufeng Wang ◽  
Genyi Zhang
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Glucose Homeostasis ◽  
Hepatic Insulin Resistance ◽  
Obese Mice ◽  
Structural Form ◽  
Whole Grain ◽  
Hepatic Insulin Sensitivity

WGLSF improves hepatic insulin resistance and glucose homeostasis in diet-induced obese mice.

scholarly journals CB1 antagonism restores hepatic insulin sensitivity without normalization of adiposity in diet-induced obese dogs

2012 ◽  
Vol 302 (10) ◽  
pp. E1261-E1268 ◽  
Author(s):  
Stella P. Kim ◽  
Orison O. Woolcott ◽  
Isabel R. Hsu ◽  
Darko Stefanoski ◽  
L. Nicole Harrison ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Direct Effect ◽  
Fat Mass ◽  
Endocannabinoid System ◽  
Hepatic Insulin Resistance ◽  
Glucose Turnover ◽  
Peripheral Tissues ◽  
Hepatic Insulin Sensitivity ◽  
Subcutaneous Adiposity

The endocannabinoid system is highly implicated in the development of insulin resistance associated with obesity. It has been shown that antagonism of the CB1 receptor improves insulin sensitivity (SI). However, it is unknown whether this improvement is due to the direct effect of CB1 blockade on peripheral tissues or secondary to decreased fat mass. Here, we examine in the canine dog model the longitudinal changes in SI and fat deposition when obesity was induced with a high-fat diet (HFD) and animals were treated with the CB1 antagonist rimonabant. SI was assessed ( n = 20) in animals fed a HFD for 6 wk to establish obesity. Thereafter, while HFD was continued for 16 additional weeks, animals were divided into two groups: rimonabant (1.25 mg·kg−1·day−1 RIM; n = 11) and placebo ( n = 9). Euglycemic hyperinsulinemic clamps were performed to evaluate changes in insulin resistance and glucose turnover before HFD ( week −6) after HFD but before treatment ( week 0) and at weeks 2, 6, 12, and 16 of treatment (or placebo) + HFD. Magnetic resonance imaging was performed to determine adiposity- related changes in SI. Animals developed significant insulin resistance and increased visceral and subcutaneous adiposity after 6 wk of HFD. Treatment with RIM resulted in a modest decrease in total trunk fat with relatively little change in peripheral glucose uptake. However, there was significant improvement in hepatic insulin resistance after only 2 wk of RIM treatment with a concomitant increase in plasma adiponectin levels; both were maintained for the duration of the RIM treatment. CB1 receptor antagonism appears to have a direct effect on hepatic insulin sensitivity that may be mediated by adiponectin and independent of pronounced reductions in body fat. However, the relatively modest effect on peripheral insulin sensitivity suggests that significant improvements may be secondary to reduced fat mass.

Adipose tissue inflammation contributes to short-term high-fat diet-induced hepatic insulin resistance

2013 ◽  
Vol 305 (3) ◽  
pp. E388-E395 ◽  
Author(s):  
Michael S. F. Wiedemann ◽  
Stephan Wueest ◽  
Flurin Item ◽  
Eugen J. Schoenle ◽  
Daniel Konrad
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Glucose Tolerance ◽  
High Fat Diet ◽  
Hepatic Insulin Resistance ◽  
Adipose Tissue Inflammation ◽  
High Fat ◽  
Hepatic Insulin Sensitivity ◽  
Tissue Inflammation

High-fat feeding for 3–4 days impairs glucose tolerance and hepatic insulin sensitivity. However, it remains unclear whether the evolving hepatic insulin resistance is due to acute lipid overload or the result of induced adipose tissue inflammation and consequent dysfunctional adipose tissue-liver cross-talk. In the present study, feeding C57Bl6/J mice a fat-enriched diet [high-fat diet (HFD)] for 4 days induced glucose intolerance, hepatic insulin resistance (as assessed by hyperinsulinemic euglycemic clamp studies), and hepatic steatosis as well as adipose tissue inflammation (i.e., TNFα expression) compared with standard chow-fed mice. Adipocyte-specific depletion of the antiapoptotic/anti-inflammatory factor Fas (CD95) attenuated adipose tissue inflammation and improved glucose tolerance as well as hepatic insulin sensitivity without altering the level of hepatic steatosis induced by HFD. In summary, our results identify adipose tissue inflammation and resulting dysfunctional adipose tissue-liver cross-talk as an early event in the development of HFD-induced hepatic insulin resistance.

Mediobasal hypothalamic PTEN modulates hepatic insulin resistance independently of food intake in rats

2014 ◽  
Vol 307 (1) ◽  
pp. E47-E60 ◽  
Author(s):  
Takashi Sumita ◽  
Hiraku Ono ◽  
Tokuko Suzuki ◽  
Gota Sakai ◽  
Kouichi Inukai ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Weight Gain ◽  
Insulin Sensitivity ◽  
Food Intake ◽  
Glucose Metabolism ◽  
Hepatic Insulin Resistance ◽  
High Fat ◽  
Hepatic Insulin Sensitivity ◽  
Constitutive Activation ◽  
Tensin Homolog

Phosphatase and tensin homolog (PTEN) dephosphorylates phosphatidylinositol (PI) 3,4,5-triphosphate and antagonizes PI 3-kinase. Insulin acts in the mediobasal hypothalamus (MBH) to not only suppress food intake and weight gain but also improve glucose metabolism via PI 3-kinase activation. Thus, the blocking of hypothalamic PTEN is a potential target for treating obesity as well as diabetes. However, genetic modification of PTEN in specific neuronal populations in the MBH yielded complex results, and no postnatal intervention for hypothalamic PTEN has been reported yet. To elucidate how postnatal modification of hypothalamic PTEN influences food intake as well as glucose metabolism, we bidirectionally altered PTEN activity in the MBH of rats by adenoviral gene delivery. Inhibition of MBH PTEN activity reduced food intake and weight gain, whereas constitutive activation of PTEN tended to induce the opposite effects. Interestingly, the effects of MBH PTEN intervention on food intake and body weight were blunted by high-fat feeding. However, MBH PTEN blockade improved hepatic insulin sensitivity even under high-fat-fed conditions. On the other hand, constitutive activation of MBH PTEN induced hepatic insulin resistance. Hepatic Akt phosphorylation and the G6Pase expression level were modulated bidirectionally by MBH PTEN intervention. These results demonstrate that PTEN in the MBH regulates hepatic insulin sensitivity independently of the effects on food intake and weight gain. Therefore, hypothalamic PTEN is a promising target for treating insulin resistance even in states of overnutrition.

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