Bethanechol and N-acetylcysteine mimic feeding signals and reverse insulin resistance in fasted and sucrose-induced diabetic rats

2011 ◽  
Vol 89 (2) ◽  
pp. 135-142 ◽  
Author(s):  
W. Wayne Lautt ◽  
Joshua Schafer ◽  
M. Paula Macedo ◽  
Dallas J. Legare
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Diabetic Rats ◽  
Similar Degree ◽  
Fasted State ◽  
Diabetes Model ◽  
Diabetic Model ◽  
Hepatic Glutathione ◽  
Necessary And Sufficient ◽  
Fasted Rats

Meal-induced insulin sensitization (MIS) is explained by the HISS (hepatic insulin sensitizing substance) hypothesis. In the presence of two “feeding signals,” a pulse of insulin results in the release of HISS from the liver. HISS acts selectively on skeletal muscle and doubles the response to insulin. HISS is not released in the fasted state or in the sucrose-supplemented diabetes model. We tested the hypothesis that provision of both feeding signals allows insulin to cause HISS release in both the normal fasted and the diabetic model. The dynamic response to insulin (50 mU/kg over 5 min) was quantified using the rapid insulin sensitivity test (RIST). Gastric injection of a liquid test meal or i.v. administration of N-acetylcysteine in 24 h fasted rats raised hepatic glutathione to a similar degree (by 46%–47%). Hepatic denervation in fed rats eliminated the parasympathetic signal and eliminated MIS, and bethanechol completely restored MIS. Both compounds administered together allowed insulin to stimulate HISS release in 24 h fasted rats and in a diabetic model (9-week, 35% liquid sucrose supplement). Neither was effective alone. Both “feeding signals” are necessary and sufficient for insulin to stimulate HISS release.

Indirect effect of catecholamines on development of insulin resistance in skeletal muscle from diabetic rats

Diabetes ◽  
1989 ◽  
Vol 38 (7) ◽  
pp. 906-910 ◽  
Author(s):  
M. Bostrom ◽  
Z. Nie ◽  
G. Goertz ◽  
J. Henriksson ◽  
H. Wallberg-Henriksson
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Indirect Effect ◽  
Diabetic Rats

Hepatic glycogen breakdown is implicated in the maintenance of plasma mannose concentration

2005 ◽  
Vol 288 (3) ◽  
pp. E534-E540 ◽  
Author(s):  
T. Taguchi ◽  
E. Yamashita ◽  
T. Mizutani ◽  
H. Nakajima ◽  
M. Yabuuchi ◽  
...  
Keyword(s):  
Glycogen Phosphorylase ◽  
Diabetic Rats ◽  
Hepatic Glycogen ◽  
Perfused Liver ◽  
Diabetes Model ◽  
Gluconeogenic Substrates ◽  
Glycogen Phosphorylase Inhibitor ◽  
Fasted Rats ◽  
Glycogen Breakdown

d-Mannose is an essential monosaccharide constituent of glycoproteins and glycolipids. However, it is unknown how plasma mannose is supplied. The aim of this study was to explore the source of plasma mannose. Oral administration of glucose resulted in a significant decrease of plasma mannose concentration after 20 min in fasted normal rats. However, in fasted type 2 diabetes model rats, plasma mannose concentrations that were higher compared with normal rats did not change after the administration of glucose. When insulin was administered intravenously to fed rats, it took longer for plasma mannose concentrations to decrease significantly in diabetic rats than in normal rats (20 and 5 min, respectively). Intravenous administration of epinephrine to fed normal rats increased the plasma mannose concentration, but this effect was negated by fasting or by administration of a glycogen phosphorylase inhibitor. Epinephrine increased mannose output from the perfused liver of fed rats, but this effect was negated in the presence of a glucose-6-phosphatase inhibitor. Epinephrine also increased the hepatic levels of hexose 6-phosphates, including mannose 6-phosphate. When either lactate alone or lactate plus alanine were administered as gluconeogenic substrates to fasted rats, the concentration of plasma mannose did not increase. When lactate was used to perfuse the liver of fasted rats, a decrease, rather than an increase, in mannose output was observed. These findings indicate that hepatic glycogen is a source of plasma mannose.

scholarly journals Mammalian Tribbles homolog 3 impairs insulin action in skeletal muscle: role in glucose-induced insulin resistance

2010 ◽  
Vol 298 (3) ◽  
pp. E565-E576 ◽  
Author(s):  
Jiarong Liu ◽  
Xuxia Wu ◽  
John L. Franklin ◽  
Joseph L. Messina ◽  
Helliner S. Hill ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Glucose Transporter ◽  
Vastus Lateralis ◽  
Glucose Deprivation ◽  
Muscle Cells ◽  
Diabetic Rats ◽  
Glucose Disposal ◽  
Insulin Resistant ◽  
Protein Levels

Tribbles homolog 3 (TRIB3) was found to inhibit insulin-stimulated Akt phosphorylation and modulate gluconeogenesis in rodent liver. Currently, we examined a role for TRIB3 in skeletal muscle insulin resistance. Ten insulin-sensitive, ten insulin-resistant, and ten untreated type 2 diabetic (T2DM) patients were metabolically characterized by hyperinsulinemic euglycemic glucose clamps, and biopsies of vastus lateralis were obtained. Skeletal muscle samples were also collected from rodent models including streptozotocin (STZ)-induced diabetic rats, db/db mice, and Zucker fatty rats. Finally, L6 muscle cells were used to examine regulation of TRIB3 by glucose, and stable cell lines hyperexpressing TRIB3 were generated to identify mechanisms underlying TRIB3-induced insulin resistance. We found that 1) skeletal muscle TRIB3 protein levels are significantly elevated in T2DM patients; 2) muscle TRIB3 protein content is inversely correlated with glucose disposal rates and positively correlated with fasting glucose; 3) skeletal muscle TRIB3 protein levels are increased in STZ-diabetic rats, db/db mice, and Zucker fatty rats; 4) stable TRIB3 hyperexpression in muscle cells blocks insulin-stimulated glucose transport and glucose transporter 4 (GLUT4) translocation and impairs phosphorylation of Akt, ERK, and insulin receptor substrate-1 in insulin signal transduction; and 5) TRIB3 mRNA and protein levels are increased by high glucose concentrations, as well as by glucose deprivation in muscle cells. These data identify TRIB3 induction as a novel molecular mechanism in human insulin resistance and diabetes. TRIB3 acts as a nutrient sensor and could mediate the component of insulin resistance attributable to hyperglycemia (i.e., glucose toxicity) in diabetes.

scholarly journals Inhibitory effect of hyperglycemia on insulin-induced Akt/protein kinase B activation in skeletal muscle

2001 ◽  
Vol 280 (5) ◽  
pp. E816-E824 ◽  
Author(s):  
Akira Oku ◽  
Masao Nawano ◽  
Kiichiro Ueta ◽  
Takuya Fujita ◽  
Itsuro Umebayashi ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Protein Kinase ◽  
Insulin Receptor ◽  
Soleus Muscle ◽  
Insulin Signaling ◽  
Skeletal Muscles ◽  
Glucose Transporter ◽  
Protein Kinase B ◽  
Diabetic Rats

To determine the molecular mechanism underlying hyperglycemia-induced insulin resistance in skeletal muscles, postreceptor insulin-signaling events were assessed in skeletal muscles of neonatally streptozotocin-treated diabetic rats. In isolated soleus muscle of the diabetic rats, insulin-stimulated 2-deoxyglucose uptake, glucose oxidation, and lactate release were all significantly decreased compared with normal rats. Similarly, insulin-induced phosphorylation and activation of Akt/protein kinase B (PKB) and GLUT-4 translocation were severely impaired. However, the upstream signal, including phosphorylation of the insulin receptor (IR) and insulin receptor substrate (IRS)-1 and -2 and activity of phosphatidylinositol (PI) 3-kinase associated with IRS-1/2, was enhanced. The amelioration of hyperglycemia by T-1095, a Na+-glucose transporter inhibitor, normalized the reduced insulin sensitivity in the soleus muscle and the impaired insulin-stimulated Akt/PKB phosphorylation and activity. In addition, the enhanced PI 3-kinase activation and phosphorylation of IR and IRS-1 and -2 were reduced to normal levels. These results suggest that sustained hyperglycemia impairs the insulin-signaling steps between PI 3-kinase and Akt/PKB, and that impaired Akt/PKB activity underlies hyperglycemia-induced insulin resistance in skeletal muscle.

scholarly journals Gymnemic acid, a potent antidiabetic agent protects skeletal muscle from hyperglycemia mediated oxidative stress and apoptotic events in High fat and High fructose diet fed adult rats

2020 ◽  
Vol 11 (2) ◽  
pp. 1526-1538
Author(s):  
Porkodi Karthikeyan ◽  
Lakshmi Narasimhan Chakrapani ◽  
Thangarajeswari Mohan ◽  
Bhavani Tamilarasan ◽  
Pughazhendi Kannan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Diabetic Rats ◽  
High Fat ◽  
Gymnemic Acid ◽  
High Fructose ◽  
Type 2 Diabetic

Type 2 diabetes is delineated by impaired metabolic flexibility, and intramyocellular lipid accumulation, causing insulin resistance, particularly in skeletal muscle by reducing insulin-stimulated glucose uptake. High-fat diet and high fructose (HFD and HF) administration in rodents bestows a model for hyperlipidemia, insulin resistance, and Type 2 diabetes. The current study is focused on elucidating the role of Gymnemic acid in combating hyperglycemia mediated oxidative stress and apoptotic events in the skeletal muscle of HFD and HF induced Type 2 diabetes in Wistar albino rats by boosting antioxidant defense system. Gymnemic acid, a saponin of triterpene glycoside contained in leaves of Gymnema Sylvestre, has potent anti-diabetic properties. Treatment with Gymnemic acid restored the antioxidant status (Gpx, SOD, CAT, GR, Vit C & Vit E) with significant (p<0.05) decrease in free radical levels and reinvigorated the expression of apoptotic and antiapoptotic proteins in Type 2 diabetic rats. Histopathological data demonstrate that oral administration of Gymnemic acid protects skeletal muscle fibers from an oxidative niche in HFD and HF in Type 2 diabetic rats. In accordance with this, Gymnemic acid might be regarded as a promising therapeutic agent against Type 2 diabetes, thereby restoring skeletal muscle integrity and function.

scholarly journals Beneficial effects of dietary restriction in type 2 diabetic rats: the role of adipokines on inflammation and insulin resistance

2010 ◽  
Vol 104 (1) ◽  
pp. 76-82 ◽  
Author(s):  
Joana Crisóstomo ◽  
Lisa Rodrigues ◽  
Paulo Matafome ◽  
Carmen Amaral ◽  
Elsa Nunes ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Dietary Restriction ◽  
Insulin Signalling ◽  
Diabetic Rats ◽  
Energy Restriction ◽  
Beneficial Effects

Inflammation plays an important role in diabetes mellitus and its complications. In this context, the negative cross-talk between adipose tissue and skeletal muscle leads to disturbances in muscle cell insulin signalling and induces insulin resistance. Because several studies have shown that energy restriction brings some benefits to diabetes, the aim of the present study was to evaluate the effects of dietary restriction on systemic and skeletal muscle inflammatory biomarkers, such C-reactive protein, adipokines and cytokines, and in insulin resistance in Goto-Kakizaki rats. This is an animal model of spontaneous non-obese type 2 diabetes with strongly insulin resistance and without dyslipidaemia. Animals were maintained during 2 months of dietary restriction (50 %) and were killed at 6 months of age. Some biochemical determinations were done using ELISA and Western blot. Data from the present study demonstrate that in Goto-Kakizaki rats the dietary restriction improved insulin resistance, NEFA levels and adipokine profile and ameliorated inflammatory cytokines in skeletal muscle. These results indicate that dietary restriction in type 2 diabetes enhances adipose tissue metabolism leading to an improved skeletal muscle insulin sensitivity.

Formation of gluconeogenic precursors in rat skeletal muscle during fasted-refed transition

1990 ◽  
Vol 259 (4) ◽  
pp. E513-E516
Author(s):  
M. N. Goodman ◽  
R. Dietrich ◽  
P. Luu
Keyword(s):  
Skeletal Muscle ◽  
Blood Lactate ◽  
Muscle Metabolism ◽  
Liver Glycogen ◽  
Hepatic Glycogen ◽  
Indirect Pathway ◽  
Rat Skeletal Muscle ◽  
Fasted State ◽  
Glycogen Repletion ◽  
Fasted Rats

During the fasted-refed transition, hepatic glycogen repletion from glucose can occur by the direct and indirect pathway. In the indirect pathway, glucose is first metabolized to 3-carbon intermediates that then are converted in the liver to glucose 6-phosphate via the gluconeogenic pathway before conversion to glycogen. The present study evaluated whether skeletal muscle is a major source of 3-carbon intermediates (i.e., lactate, pyruvate, and alanine) during refeeding of 1-day fasted rats. Arteriovenous differences for lactate, pyruvate, and alanine across the anesthetized rat hindlimbs were used to evaluate muscle metabolism in the fed, fasted, and refed state. In the fasted state, liver glycogen was depleted, and muscle released 3-carbon intermediates. One hour after refeeding, hepatic glycogen was 30% repleted, and blood lactate, pyruvate, and alanine increased. Despite this, the release of alanine by muscle diminished at this time and lactate was removed. At 4 h after refeeding, 3-carbon intermediates were all released by hindlimb tissue but in an amount not greater than in the fasted state. Overall, these results suggest that skeletal muscle in the rat is not a major source of 3-carbon precursors for early postprandial hepatic glycogen repletion via the indirect pathway, nor is the rise in 3-carbon intermediates in blood during refeeding caused by their increased output by muscle.

Insulin stimulates phenylalanine uptake across the hind limb in fed lambs

1999 ◽  
Vol 1999 ◽  
pp. 162-162
Author(s):  
T.J Wester ◽  
G.E. Lobley ◽  
L.M. Birnie ◽  
M.A. Lomax
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Hind Limb ◽  
Muscle Protein ◽  
Branched Chain Amino Acids ◽  
Anabolic Effect ◽  
Skeletal Muscle Protein ◽  
Fasted State ◽  
Branched Chain ◽  
Fasted Rats

Although insulin has been shown to stimulate muscle protein accretion in nonruminants (e.g., Wray-Cahen et al., 1998) evidence for this same effect in ruminants has been equivocal (e.g., Oddy et al., 1987; Wolff et al., 1989). Moreover, when insulin has been reported to have an anabolic effect in ruminants, the animal has been in the fasted state. In addition, Garlick and Grant (1988) have shown that branched-chain amino acids (BCAA) enhanced insulin-stimulated protein synthesis in fasted rats. The primary aim of the present study was to ascertain whether insulin increases phenylalanine (Phe) uptake (used as an index of skeletal muscle protein anabolism) across the hind limb of fed lambs. A secondary aim was to determine if infusion of BCAA, alone or in combination with insulin, would stimulate Phe uptake greater than insulin alone.

scholarly journals Effects of Modified Sanzi Yangqin Decoction on Tyrosine Phosphorylation of IRS-1 in Skeletal Muscle of Type 2 Diabetic Rats

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Ya Wang ◽  
Xiaojin La ◽  
Chunyu Tian ◽  
Yushan Dong ◽  
Feng Qi ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Tyrosine Phosphorylation ◽  
Resistance Index ◽  
Diabetic Rats ◽  
C Peptide ◽  
Insulin Resistance Index ◽  
Peptide Level ◽  
Type 2 Diabetic

This study aimed to investigate the effect of Modified Sanzi Yangqin Decoction on tyrosine phosphorylation of insulin receptor substrate 1 (IRS-1) in skeletal muscle of type 2 diabetic rats. The rat model of type 2 diabetes was induced by high-fat diet and multiple low-dose streptozotocin injections. Diabetic model rats were randomly divided into 5 groups: the model control group, the metformin group, and Modified Sanzi Yangqin Decoction groups of low, medium, and high doses. OGTT was conducted every two weeks during treatment period. At the end of the treatment, the fasting blood glucose (FBG) level and the fasting C-peptide level were measured to calculate insulin resistance index. The levels of IRS-1, p-IRS-1Tyr895, and protein tyrosine phosphates 1B (PTP1B) in skeletal muscle were also measured. Modified Sanzi Yangqin Decoction significantly reduced the FBG level, increased the fasting C-peptide level, and lowered the insulin resistance index in type 2 diabetic rats. It also significantly increased the protein level of p-IRS-1Tyr895 and reduced the PTP1B protein level in skeletal muscle of type 2 diabetic rats. Modified Sanzi Yangqin Decoction increases tyrosine phosphorylation of IRS-1 in skeletal muscle of type 2 diabetic rats, which results from the increase of p-IRS-1Tyr895 protein and is related to the suppression of PTP1B protein.

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