Fat distribution and storage: how much, where, and how?

2007 ◽  
Vol 157 (suppl_1) ◽  
pp. S39-S45 ◽  
Author(s):  
Ram Weiss
Keyword(s):  
Insulin Resistance ◽  
Signal Transduction Pathway ◽  
Insulin Resistance Syndrome ◽  
Fat Distribution ◽  
Good Health ◽  
Lipid Deposition ◽  
Insulin Signal Transduction ◽  
Underlying Mechanisms ◽  
Insulin Signal Transduction Pathway ◽  
Inflammatory Milieu

Obesity does not necessarily imply disease and similarly obese individuals may manifest obesity-related morbidity or seemingly be in reasonably good health. Recent studies have shown that patterns of lipid partitioning are a major determinant of the metabolic profile and not just obesity per se. The underlying mechanisms and clinical relevance of lipid deposition in the visceral compartment and in insulin-sensitive tissues are described. Increased intramyocellular lipid deposition impairs the insulin signal transduction pathway and is associated with insulin resistance. Increased hepatic lipid deposition is similarly associated with the majority of the components of the insulin resistance syndrome. The roles of increased circulating fatty acids in conditions of insulin resistance and the typical pro-inflammatory milieu of specific obesity patterns are provided. Insights into the patterns of lipid storage within the cell are provided along with their relation to changes in insulin sensitivity and weight loss.

Natural Alkaloids Intervening the Insulin Pathway: New Hopes for Anti-Diabetic Agents?

2019 ◽  
Vol 26 (32) ◽  
pp. 5982-6015 ◽  
Author(s):  
Maria-Ioanna Christodoulou ◽  
Job Tchoumtchoua ◽  
Alexios-Leandros Skaltsounis ◽  
Andreas Scorilas ◽  
Maria Halabalaki
Keyword(s):  
Insulin Resistance ◽  
Insulin Signaling ◽  
Signal Transduction Pathway ◽  
Insulin Signal Transduction ◽  
Risk Of Death ◽  
Increased Risk ◽  
Expression Activity ◽  
Insulin Signal Transduction Pathway

Background: Accumulating experimental data supports the capacity of natural compounds to intervene in complicated molecular pathways underlying the pathogenesis of certain human morbidities. Among them, diabetes is now a world’s epidemic associated with increased risk of death; thus, the detection of novel anti-diabetic agents and/or adjuvants is of vital importance. Alkaloids represent a diverse group of natural products with a range of therapeutic properties; during the last 20 years, published research on their anti-diabetic capacity has been tremendously increased. Purpose: To discuss current concepts on the anti-diabetic impact of certain alkaloids, with special reference to their molecular targets throughout the insulin-signaling pathway. Methodology: Upon in-depth search in the SCOPUS and PUBMED databases, the literature on alkaloids with insulin secretion/sensitization properties was critically reviewed. Results: In-vitro and in-vivo evidence supports the effect of berberine, trigonelline, piperine, oxymatrine, vindoneline, evodiamine and neferine on insulin-signaling and related cascades in beta-cells, myocytes, adipocytes, hepatocytes and other cells. Associated receptors, kinases, hormones and cytokines, are affected in terms of gene transcription, protein expression, activity and/or phosphorylation. Pathophysiological processes associated with insulin resistance, beta-cell failure, oxidative stress and inflammation, as well as clinical phenotype are also influenced. Discussion: Growing evidence suggests the ability of specific alkaloids to intervene in the insulin-signal transduction pathway, reverse molecular defects resulting in insulin resistance and glucose intolerance and improve disease complications, in-vitro and in-vivo. Future indepth molecular studies are expected to elucidate their exact mechanism of action, while large clinical trials are urgently needed to assess their potential as anti-diabetic agents.

scholarly journals Signal Transducer and Activator of Transcription (Stat)-Induced Stat Inhibitor 1 (Ssi-1)/Suppressor of Cytokine Signaling 1 (Socs1) Inhibits Insulin Signal Transduction Pathway through Modulating Insulin Receptor Substrate 1 (Irs-1) Phosphorylation

2001 ◽  
Vol 193 (2) ◽  
pp. 263-270 ◽  
Author(s):  
Yoshinori Kawazoe ◽  
Tetsuji Naka ◽  
Minoru Fujimoto ◽  
Hidetsugu Kohzaki ◽  
Yoshiaki Morita ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Negative Feedback ◽  
Signal Transduction Pathway ◽  
Cytokine Signaling ◽  
Insulin Receptor Substrate ◽  
Signal Transducer ◽  
Transduction Pathway ◽  
Insulin Signal Transduction ◽  
Insulin Signal ◽  
Insulin Signal Transduction Pathway

Signal transducer and activator of transcription (STAT)-induced STAT inhibitor 1 (SSI-1) is known to function as a negative feedback regulator of cytokine signaling, but it is unclear whether it is involved in other biological events. Here, we show that SSI-1 participates and plays an important role in the insulin signal transduction pathway. SSI-1–deficient mice showed a significantly low level of blood sugar. While the forced expression of SSI-1 reduced the phosphorylation level of insulin receptor substrate 1 (IRS-1), SSI-1 deficiency resulted in sustained phosphorylation of IRS-1 in response to insulin. Furthermore, SSI-1 achieves this inhibition both by binding directly to IRS-1 and by suppressing Janus kinases. These findings suggest that SSI-1 acts as a negative feedback factor also in the insulin signal transduction pathway through the suppression of IRS-1 phosphorylation.

scholarly journals Antenatal corticosteroids alter insulin signaling pathways in fetal baboon skeletal muscle

2014 ◽  
Vol 221 (2) ◽  
pp. 253-260 ◽  
Author(s):  
Cynthia L Blanco ◽  
Alvaro G Moreira ◽  
Lisa L McGill-Vargas ◽  
Diana G Anzueto ◽  
Peter Nathanielsz ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Content ◽  
Insulin Signaling ◽  
Vastus Lateralis ◽  
Signal Transduction Pathway ◽  
Vastus Lateralis Muscle ◽  
Fetal Life ◽  
Antenatal Corticosteroids ◽  
Insulin Signal Transduction ◽  
Insulin Signal Transduction Pathway

We hypothesize that prenatal exposure to glucocorticoids (GCs) negatively alters the insulin signal transduction pathway and has differing effects on the fetus according to gestational age (GA) at exposure. Twenty-three fetal baboons were delivered from 23 healthy, nondiabetic mothers. Twelve preterm (0.67 GA) and 11 near-term (0.95 GA) baboons were killed immediately after delivery. Half of the pregnant baboons at each gestation received two doses of i.m. betamethasone 24 h apart (170 μg/kg) before delivery, while the other half received no intervention. Vastus lateralis muscle was obtained from postnatal animals to measure the protein content and gene expression of insulin receptor β (IRβ; INSR), IRβ Tyr 1361 phosphorylation (pIRβ), IR substrate 1 (IRS1), IRS1 tyrosine phosphorylation (pIRS1), p85 subunit of PI3-kinase, AKT (protein kinase B), phospho-AKT Ser473 (pAKT), AKT1, AKT2, and glucose transporters (GLUT1 and GLUT4). Skeletal muscle from preterm baboons exposed to GCs had markedly reduced protein content of AKT and AKT1 (respectively, 73 and 72% from 0.67 GA control, P<0.001); IRβ and pIRβ were also decreased (respectively, 94 and 85%, P<0.01) in the muscle of premature GC-exposed fetuses but not in term fetuses. GLUT1 and GLUT4 tended to increase with GC exposure in preterm animals (P=0.09), while GLUT4 increased sixfold in term animals after exposure to GC (P<0.05). In conclusion, exposure to a single course of antenatal GCs during fetal life alters the insulin signaling pathway in fetal muscle in a manner dependent on the stage of gestation.

scholarly journals PI3 kinase directly phosphorylates Akt1/2 at Ser473/474 in the insulin signal transduction pathway

2013 ◽  
Vol 220 (1) ◽  
pp. 49-59 ◽  
Author(s):  
A Tsuchiya ◽  
T Kanno ◽  
T Nishizaki
Keyword(s):  
Signal Transduction ◽  
Glucose Transporter ◽  
Signal Transduction Pathway ◽  
Significant Inhibition ◽  
Dependent Manner ◽  
Transduction Pathway ◽  
Glut4 Translocation ◽  
Insulin Signal Transduction ◽  
Insulin Signal ◽  
Insulin Signal Transduction Pathway

Insulin stimulated translocation of the glucose transporter GLUT4 from the cytosol to the plasma membrane in a concentration (1 nM–1 μM)-dependent manner and increased glucose uptake in 3T3-L1 adipocytes. Insulin-induced GLUT4 translocation to the cell surface was prevented by the phosphoinositide 3 kinase (PI3K) inhibitor wortmannin, the 3-phosphoinositide-dependent protein kinase 1 (PDK1) inhibitor BX912 or the Akt1/2 inhibitor MK2206, and by knocking-down PI3K, PDK1 or Akt1/2. Insulin increased phosphorylation of Akt1/2 at Thr308/309 and Ser473/474, to activate Akt1/2, in the adipocytes. Insulin-induced phosphorylation of Akt1/2 was suppressed by wortmannin and knocking-down PI3K, while no significant inhibition of the phosphorylation was obtained with BX912 or knocking-down PDK1. In the cell-free Akt assay, PI3K phosphorylated Akt1 both at Thr308 and Ser473 and Akt2 at Ser474 alone. In contrast, PDK1 phosphorylates Akt1 at Thr308 and Akt2 at Thr309. The results of this study indicate that PI3K activates Akt1, independently of PDK1, and Akt2 by cooperating with PDK1 in the insulin signal transduction pathway linked to GLUT4 translocation.

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