scholarly journals Possible interactions between angiotensin II and insulin: effects on glucose and lipid metabolism in vivo and in vitro

2000 ◽  
Vol 167 (3) ◽  
pp. 525-531 ◽  
Author(s):  
D Patiag ◽  
X Qu ◽  
S Gray ◽  
I Idris ◽  
M Wilkes ◽  
...  

Angiotensin II (ANGII) increases insulin sensitivity in diabetic and non-diabetic subjects, even at subpressor doses, and because there is 'crosstalk' between ANGII and insulin-signaling pathways the underlying mechanism may not be due solely to changes in regional blood flow. A series of experimental studies was undertaken to evaluate the effects of ANGII on glucose and lipid metabolism in vivo and in vitro. Groups of fructose-fed, insulin-resistant Sprague-Dawley (SD) rats were pre-treated with 0.3 mg/kg per day of the AT(1)-receptor antagonist L-158 809 (n=16), or vehicle (n=16), by oral gavage. This was prior to an oral glucose tolerance test (day 5) and measurement of the effects of ANGII infusion (20 ng/kg per min i.v. for 3 h) on whole-body insulin sensitivity using the insulin suppression test (day 7). The effect of ANGII infusion on total triglyceride secretion rate (TGSR) was evaluated in normal SD rats pretreated for 7 days with L-158 809 (n=12) or vehicle (n=12). AT(1)- and AT(2)- receptor mRNA expression and [(3)H]2-deoxyglucose uptake were assessed in cultured L6 myoblasts. Short-term treatment with L-158 809 had no effect on glucose tolerance or fasting triglyceride levels in fructose-fed rats. ANGII infusion had no effect on insulin sensitivity in fructose-fed rats pretreated with vehicle (steady-state plasma glucose (SSPG) values 8.1+/-1.6 vs 8. 4+/-0.4 mmol/l), but pretreatment with L-158 809 resulted in ANGII having a modest insulin antagonist effect in this insulin-resistant model (SSPG values 9.6+/-0.3 vs 7.1+/-0.6, P<0.03). ANGII infusion had no significant effect on TGSR (e.g. 24.6+/-1.4 vs 28.4+/-0.9 mg/100 g per h in vehicle-treated animals). RT-PCR analysis showed that L6 cells express both AT(1)- and AT(2)-receptor mRNA. Incubation with ANGII (10(-9) and 10(-8) M) had no significant effect on the dose-response curve for insulin-stimulated [(3)H]2-deoxyglucose uptake. For example, C(I200) values (dose of insulin required to increase glucose uptake by 200%) were 4.5 x 10(-9) M (control) vs 3.9 x 10(-9) M and 6.2 x 10(-9) M, whereas the positive control (glucagon-like peptide-1) increased insulin sensitivity. Thus, ANGII infusion may have a modest insulin antagonist effect on glucose disposal in insulin-resistant fructose-fed rats pretreated with an AT(1)-blocker, but ANGII has no effect on TGSR or in vitro glucose uptake in L6 myoblasts. These findings are relevant to recent clinical discussions about the metabolic effects of ANGII and renin-angiotensin system blockade.

1992 ◽  
Vol 127 (4) ◽  
pp. 344-350 ◽  
Author(s):  
Allan A Vaag ◽  
Henning Beck-Nielsen

The effect of prolonged treatment with Acipimox on in vivo peripheral insulin sensitivity, and on glucose and lipid metabolism, was investigated in patients with NIDDM in a double-blind study. Twelve NIDDM patients were randomized to treatment with either placebo or Acipimox in pharmacological doses (250 mg×3) for three months. Fasting plasma glucose, insulin, C-peptide and HbA1c concentrations were unaffected after three months of acipimox treatment. However, fasting plasma non-esterifled fatty acid (NEFA) concentrations were twofold elevated after Acipimox treatment (1.34±0.09 vs 0.66±0.09 mmol/l; p<0.05). Despite this, repeated acute Acipimox administration after the three months' treatment period enhanced total insulin-stimulated glucose disposal to the same extent as acute Acipimox administration before the treatment period (367±59 vs 392±66 mg·m−2·min−1, NS; both p<0.05 vs placebo glucose disposal) (267±44 mg·m−2·min−1). In conclusion, insulin resistance or tachyphylaxis towards the effects of Acipimox on insulin stimulated glucose disposal was not induced during prolonged Acipimox treatment. The lack of improvement of blood glucose control in the patients with NIDDM may be due to the demonstrated rebound effect of lipolysis.


1996 ◽  
Vol 270 (2) ◽  
pp. E344-E352 ◽  
Author(s):  
A. T. Ozcelikay ◽  
D. J. Becker ◽  
L. N. Ongemba ◽  
A. M. Pottier ◽  
J. C. Henquin ◽  
...  

Molybdenum mimics certain insulin actions in vitro. We have investigated the effects of oral administration of Na2MoO4 (Mo) for 8 wk on carbohydrate and lipid metabolism in streptozotocin-diabetic rats. Mo decreased hyperglycemia and glucosuria by 75% and corrected the elevation of plasma nonesterified fatty acids. Tolerance to glucose loads was improved, and glycogen stores were replenished. These effects were not due to a rise of insulinemia. In liver, Mo restored the blunted mRNA and activity of glucokinase and pyruvate kinase and decreased to normal phosphoenolpyruvate carboxykinase values. Finally, Mo totally reversed the low expression and activity of acetyl-CoA carboxylase and fatty acid synthase in liver, but not in white adipose tissue. In conclusion, Mo exerts a marked blood glucose-lowering effect in diabetic rats by an insulin-like action. This effect results in part from a restoration of hepatic glucose metabolism and is associated with a tissue-specific correction of lipogenic enzyme gene expression, both processes being essentially mediated by reversal of impaired pretranslational regulatory mechanisms. These observations raise new therapeutic perspectives in diabetes, particularly in the insulin-resistant condition.


2006 ◽  
Vol 154 (1) ◽  
pp. 83-86 ◽  
Author(s):  
S Corbetta ◽  
R Angioni ◽  
A Cattaneo ◽  
P Beck-Peccoz ◽  
A Spada

Objective: In vitro and in vivo models indicate that all-trans retinoic acids influence glucose and lipid metabolism. We aimed to evaluate the effects of chronic treatment with acitretin, an all-trans retinoic acid, on glucose metabolism, lipid profile and adiponectin and resistin levels. Design: Ten normoglycemic, normolipemic patients affected with psoriasis vulgaris were studied before and after 1 and 3 months of oral treatment with 35 μg of acitretin. Methods: Glucose metabolism, lipid profile, and adiponectin and resistin levels were evaluated in basal conditions and after acitretin treatment. Ten healthy subjects matched for age, body mass index (BMI) and insulin sensitivity were studied as controls. Results: One-month acitretin treatment reduced psoriasis activity, insulin sensitivity, evaluated as QUICKI values (0.364 ± 0.034 versus 0.329 ± 0.051; P < 0.05) and HOMA-IR index (1.53 ± 0.73 versus 2.59 ± 1.41; P < 0.05), and high-density lipoprotein (HDL)-cholesterol levels (45.2 ± 11.7 versus 39.4 ± 10.4 mg/dl; P = 0.01). The impairment in glucose and lipid homeostasis was transient and not associated to BMI variations. Adiponectin levels did not change during the treatment, while resistin levels, which were higher in untreated patients than in controls (9.4 ± 4.4 versus 6.2 ± 2.1 ng/ml; P = 0.05), fell within the normal range after 1 and 3 months of therapy. The normalization of resistin levels occurred without significant changes in circulating tumor necrosis factor α (TNFα) levels, which persisted elevated throughout the treatment. Conclusions: Treatment with a low dose of acitretin induced a mild, transient reduction of insulin sensitivity and HDL-cholesterol levels that was not related to modifications of adiponectin, resistin and TNFα levels. Although the role of resistin in humans remains elusive, the levels of this adipocytokine seem to be affected, at least in part, by retinoids.


2020 ◽  
Vol 18 ◽  
pp. 100427 ◽  
Author(s):  
Xiao Yan ◽  
Chaobin Qin ◽  
Dapeng Deng ◽  
Guokun Yang ◽  
Junchang Feng ◽  
...  

1997 ◽  
Vol 273 (5) ◽  
pp. E859-E867 ◽  
Author(s):  
M. Hettiarachchi ◽  
S. Chalkley ◽  
S. M. Furler ◽  
Y.-S. Choong ◽  
M. Heller ◽  
...  

To clarify roles of amylin, we investigated metabolic responses to rat amylin-(8—37), a specific amylin antagonist, in normal and insulin-resistant, human growth hormone (hGH)-infused rats. Fasting conscious rats were infused with saline or hGH, each with and without amylin-(8—37) (0.125 μmol/h), over 5.75 h. At 3.75 h, a hyperinsulinemic (100 mU/l) clamp with bolus 2-deoxy-d-[3H]glucose and [14C]glucose was started. hGH infusion led to prompt (2- to 3-fold) basal hyperamylinemia ( P < 0.02) and hyperinsulinemia. Amylin-(8—37) reduced plasma insulin ( P < 0.001) and enhanced several measures of whole body and muscle insulin sensitivity ( P < 0.05) in both saline- and hGH-infused rats. Amylin-(8—37) corrected hGH-induced liver insulin resistance, increased basal plasma triglycerides and lowered plasma nonesterified fatty acids in both groups, and reduced muscle triglyceride and total long-chain acyl-CoA content in saline-treated rats ( P < 0.05). In isolated soleus muscle, amylin-(8—37) blocked amylin-induced inhibition of glycogen synthesis but had no effect in the absence of amylin. Thus 1) hyperamylinemia accompanies insulin resistance induced by hGH infusion; 2) amylin-(8—37) increases whole body and muscle insulin sensitivity and consistently reduces basal insulin levels in normal and hGH-induced insulin-resistant rats; and 3) amylin-(8—37) elicits a significant alteration of in vivo lipid metabolism. These findings support a role of amylin in modulating insulin action and suggest that this could be mediated by effects on lipid metabolism.


Author(s):  
Zhen Sun ◽  
Lili Zhang ◽  
Lihua Li ◽  
Chen Shao ◽  
Jia Liu ◽  
...  

Pathological cardiac remodeling is a leading cause of mortality in diabetic patients. Given the glucose and lipid metabolism disorders (GLD) in diabetic patients, it is urgent to conduct a comprehensive study of the myocardial damage under GLD and find key mechanisms. Apolipoprotein E knockout (ApoE-/-) mice, low-density lipoprotein receptor heterozygote (Ldlr+/-) syrian golden hamsters or H9C2 cells were used to construct GLD models -. And GLD significantly promoted cardiomyocyte fibrosis, apoptosis and hypertrophy in vivo and in vitro, while inhibition of galectin-3 (Gal-3) could significantly reverse this process. Then, the signal transmission pathways were determined. It was found that GLD considerably inhibited the phosphorylation of Akt at Thr308 / Ser473, whereas the silencing of Gal-3 could reverse the inhibition of Akt activity through PI3K-AktThr308 and AMPK-mTOR2-AktSer473 pathways. Finally, the PI3K, mTOR, AMPK inhibitor and Akt activator were used to investigate the role of pathways in regulating cardiac remodeling. Phospho-AktThr308 could mediate myocardial fibrosis, while myocardial apoptosis and hypertrophy were regulated by both phospho-AktThr308 and phospho-AktSer473. In conclusion, Gal-3 was an important regulatory factor in GLD-induced cardiac remodeling, and Gal-3 could suppress the phosphorylation of Akt at different sites in mediating cardiomyocyte fibrosis, apoptosis and hypertrophy.


2022 ◽  
Vol 22 ◽  
pp. 100930
Author(s):  
Liping Yang ◽  
Wenlei Zhang ◽  
Shaoyang Zhi ◽  
Mingyu Liu ◽  
Mengjuan Zhao ◽  
...  

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