Effects of Lipoic Acid on Insulin Action in Animal Models of Insulin Resistance

Author(s):  
Erik Henriksen ◽  
Stephan Jacob
2000 ◽  
Vol 83 (S1) ◽  
pp. S85-S90 ◽  
Author(s):  
Len H. Storlien ◽  
J. A. Higgins ◽  
T. C. Thomas ◽  
M. A. Brown ◽  
H. Q. Wang ◽  
...  

Critical insights into the etiology of insulin resistance have been gained by the use of animal models where insulin action has been modulated by strictly controlled dietary interventions not possible in human studies. Overall, the literature has moved from a focus on macronutrient proportions to understanding the unique effects of individual subtypes of fats, carbohydrates and proteins. Substantial evidence has now accumulated for a major role of dietary fat subtypes in insulin action. Intake of saturated fats is strongly linked to development of obesity and insulin resistance, while that of polyunsaturated fats (PUFAs) is not. This is consistent with observations that saturated fats are poorly oxidized for energy and thus readily stored, are poorly mobilized by lipolytic stimuli, impair membrane function, and increase the expression of genes associated with adipocyte profileration (making their own home). PUFAs have contrasting effects in each instance. It is therefore not surprising that increased PUFA intake in animal models is associated with improved insulin action and reduced adiposity. Less information is available for carbohydrate subtypes. Early work clearly demonstrated that diets high in simple sugars (in particular fructose) led to insulin resistance. However, again attention has rightly shifted to the very interesting issue of subtypes of complex carbohydrates. While no differences in insulin action have yet been shown, differences in substrate flux suggest there could be long-term beneficial effects on the fat balance of diets enhanced in slowly digested/resistant starches. A new area of major interest is in protein subtypes. Recent results have shown that rats fed high-fat diets where the protein component was from casein or soy were insulin-resistant, but when the protein source was from cod they were not. These are exciting times in our growing understanding of dietary factors and insulin action. While it has been clear for some time that ‘oils ain't oils’, the same is now proving true for carbohydrates and proteins.


1987 ◽  
Vol 22 (3) ◽  
pp. 286-291 ◽  
Author(s):  
Mitchell E Geffner ◽  
Solomon A Kaplan ◽  
Noelle Bersch ◽  
Barbara M Lippe ◽  
Wesley G Smith ◽  
...  

2018 ◽  
Vol 21 (3) ◽  
pp. 269-273 ◽  
Author(s):  
Cinzia Cavestro ◽  
Giorgio Bedogni ◽  
Filippo Molinari ◽  
Silvia Mandrino ◽  
Eugenia Rota ◽  
...  

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Yang-wei Wang ◽  
Guang-dong Sun ◽  
Jing Sun ◽  
Shu-jun Liu ◽  
Ji Wang ◽  
...  

Diabetes mellitus, especially type 2 diabetes (T2DM), is one of the most common chronic diseases and continues to increase in numbers with large proportion of health care budget being used. Many animal models have been established in order to investigate the mechanisms and pathophysiologic progress of T2DM and find effective treatments for its complications. On the basis of their strains, features, advantages, and disadvantages, various types of animal models of T2DM can be divided into spontaneously diabetic models, artificially induced diabetic models, and transgenic/knockout diabetic models. Among these models, the spontaneous rodent models are used more frequently because many of them can closely describe the characteristic features of T2DM, especially obesity and insulin resistance. In this paper, we aim to investigate the current available spontaneous rodent models for T2DM with regard to their characteristic features, advantages, and disadvantages, and especially to describe appropriate selection and usefulness of different spontaneous rodent models in testing of various new antidiabetic drugs for the treatment of type 2 diabetes.


2017 ◽  
Vol 114 (40) ◽  
pp. E8478-E8487 ◽  
Author(s):  
Masahiro Konishi ◽  
Masaji Sakaguchi ◽  
Samuel M. Lockhart ◽  
Weikang Cai ◽  
Mengyao Ella Li ◽  
...  

Insulin receptors (IRs) on endothelial cells may have a role in the regulation of transport of circulating insulin to its target tissues; however, how this impacts on insulin action in vivo is unclear. Using mice with endothelial-specific inactivation of the IR gene (EndoIRKO), we find that in response to systemic insulin stimulation, loss of endothelial IRs caused delayed onset of insulin signaling in skeletal muscle, brown fat, hypothalamus, hippocampus, and prefrontal cortex but not in liver or olfactory bulb. At the level of the brain, the delay of insulin signaling was associated with decreased levels of hypothalamic proopiomelanocortin, leading to increased food intake and obesity accompanied with hyperinsulinemia and hyperleptinemia. The loss of endothelial IRs also resulted in a delay in the acute hypoglycemic effect of systemic insulin administration and impaired glucose tolerance. In high-fat diet-treated mice, knockout of the endothelial IRs accelerated development of systemic insulin resistance but not food intake and obesity. Thus, IRs on endothelial cells have an important role in transendothelial insulin delivery in vivo which differentially regulates the kinetics of insulin signaling and insulin action in peripheral target tissues and different brain regions. Loss of this function predisposes animals to systemic insulin resistance, overeating, and obesity.


1982 ◽  
Vol 243 (1) ◽  
pp. E15-E30 ◽  
Author(s):  
J. M. Olefsky ◽  
O. G. Kolterman ◽  
J. A. Scarlett

Resistance to the action of insulin can result from a variety of causes, including the formation of abnormal insulin or proinsulin molecules, the presence of circulating antagonists to insulin or the insulin receptor, or defects in insulin action at the target tissue level. Defects of the latter type are characteristic of obesity and of noninsulin-dependent diabetes mellitus. Analysis of the nature of the insulin resistance in those disorders has been investigated in intact subjects with the use of the euglycemic glucose clamp technique, and both insulin receptors and insulin-mediated glucose metabolism have been studied in adipocytes and monocytes from affected individuals. In both conditions, the cause of insulin resistance is heterogeneous. In some, insulin resistance appears to be due to a defect in the insulin receptor, whereas others have a defect both in the receptor and at the postreceptor level. In both groups, more severe insulin resistance is due to the postreceptor lesion and is correctable with appropriate therapy.


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