scholarly journals Muscle insulin resistance resulting from impaired microvascular insulin sensitivity in Sprague Dawley rats

2013 ◽  
Vol 98 (1) ◽  
pp. 28-36 ◽  
Author(s):  
Dino Premilovac ◽  
Eloise A. Bradley ◽  
Huei L.H. Ng ◽  
Stephen M. Richards ◽  
Stephen Rattigan ◽  
...  
Author(s):  
Nicole Eleanore Jacqueline Lovat ◽  
Dallas J. Legare ◽  
W. Wayne Lautt

This study developed an animal model of gestational obesity and prediabetes in Sprague Dawley rats using 35% sucrose supplementation (SS). Postprandially, insulin stimulates glucose uptake and nutrient partitioning via insulin-dependent as well as Hepatic Insulin Sensitizing Substance (HISS)-dependent action. HISS is glycogenic in heart, kidney, and skeletal muscle (contrasting insulin’s lipogenic actions in liver and adipose tissue) and is responsible for the vasodilatory action of insulin. Post-prandial insulin sensitivity was quantified using the Rapid Insulin Sensitivity Test (RIST). 15-day gestation and virgin animals received SS for 8-weeks (with a 2-week recovery), 10-weeks or 22-weeks. SS in pregnant and virgin rats eliminated HISS-dependent glucose uptake, resulting in compensatory hyperinsulinemia and resultant hypertriglyceridemia and obesity. In groups with SS for 8-weeks followed by a 2-week recovery, there was spontaneous partial recovery of HISS-dependent glucose uptake in virgins and complete recovery in pregnancy. 10-week SS resulted in complete absence of HISS-dependent glucose uptake and produced a model of gestational obesity and prediabetes. 22-week SS did not produce hyperglycemia or worsen hyperinsulinemia but did increase hypertriglyceridemia above 10-week SS. This substantiates the use of 10-week SS as a model of gestational obesity/prediabetes, allowing further studies into treatments of gestational obesity and insulin resistance.


2008 ◽  
Vol 295 (5) ◽  
pp. E1269-E1276 ◽  
Author(s):  
J. Cacho ◽  
J. Sevillano ◽  
J. de Castro ◽  
E. Herrera ◽  
M. P. Ramos

Insulin resistance plays a role in the pathogenesis of diabetes, including gestational diabetes. The glucose clamp is considered the gold standard for determining in vivo insulin sensitivity, both in human and in animal models. However, the clamp is laborious, time consuming and, in animals, requires anesthesia and collection of multiple blood samples. In human studies, a number of simple indexes, derived from fasting glucose and insulin levels, have been obtained and validated against the glucose clamp. However, these indexes have not been validated in rats and their accuracy in predicting altered insulin sensitivity remains to be established. In the present study, we have evaluated whether indirect estimates based on fasting glucose and insulin levels are valid predictors of insulin sensitivity in nonpregnant and 20-day-pregnant Wistar and Sprague-Dawley rats. We have analyzed the homeostasis model assessment of insulin resistance (HOMA-IR), the quantitative insulin sensitivity check index (QUICKI), and the fasting glucose-to-insulin ratio (FGIR) by comparing them with the insulin sensitivity (SIClamp) values obtained during the hyperinsulinemic-isoglycemic clamp. We have performed a calibration analysis to evaluate the ability of these indexes to accurately predict insulin sensitivity as determined by the reference glucose clamp. Finally, to assess the reliability of these indexes for the identification of animals with impaired insulin sensitivity, performance of the indexes was analyzed by receiver operating characteristic (ROC) curves in Wistar and Sprague-Dawley rats. We found that HOMA-IR, QUICKI, and FGIR correlated significantly with SIClamp, exhibited good sensitivity and specificity, accurately predicted SIClamp, and yielded lower insulin sensitivity in pregnant than in nonpregnant rats. Together, our data demonstrate that these indexes provide an easy and accurate measure of insulin sensitivity during pregnancy in the rat.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Saira Tanweer ◽  
Tariq Mehmood ◽  
Saadia Zainab ◽  
Zulfiqar Ahmad ◽  
Muhammad Ammar Khan ◽  
...  

Purpose Innovative health-promoting approaches of the era have verified phytoceutics as one of the prime therapeutic tools to alleviate numerous health-related ailments. The purpose of this paper is to probe the nutraceutic potential of ginger flowers and leaves against hyperglycemia. Design/methodology/approach The aqueous extracts of ginger flowers and leaves were observed on Sprague Dawley rats for 8 weeks. Two parallel studies were carried out based on dietary regimes: control and hyperglycemic diets. At the end of the experimental modus, the overnight fed rats were killed to determine the concentration of glucose and insulin in serum. The insulin resistance and insulin secretions were also calculated by formulae by considering fasting glucose and fasting insulin concentrations. Furthermore, the feed and drink intakes, body weight gain and hematological analysis were also carried out. Findings In streptozotocin-induced hyperglycemic rats, the ginger flowers extract depicted 5.62% reduction; however, ginger leaves extract reduced the glucose concentration up to 7.11% (p = 0.001). Similarly, ginger flowers extract uplifted the insulin concentration up to 3.07%, while, by ginger leaves extract, the insulin value increased to 4.11% (p = 0.002). For the insulin resistance, the ginger flower showed 5.32% decrease; however, the insulin resistance was reduced to 6.48% by ginger leaves (p = 0.014). Moreover, the insulin secretion increased to 18.9% by flower extract and 21.8% by ginger leave extract (p = 0.001). The feed intake and body weight gain increased momentously by the addition of ginger flowers and leaves; however, the drink intake and hematological analysis remained non-significant by the addition of ginger parts. Originality/value Conclusively, it was revealed that leaves have more hypoglycemic potential as compared to flowers.


Hypertension ◽  
2005 ◽  
Vol 46 (4) ◽  
pp. 806-811 ◽  
Author(s):  
Gerard D’Angelo ◽  
Ahmed A. Elmarakby ◽  
David M. Pollock ◽  
David W. Stepp

2002 ◽  
Vol 282 (2) ◽  
pp. E412-E418 ◽  
Author(s):  
Frédéric Picard ◽  
André Boivin ◽  
Josée Lalonde ◽  
Yves Deshaies

This study aimed to assess whether adipose lipoprotein lipase (LPL) becomes resistant to insulin in a nutritional model of resistance of glucose metabolism to insulin. Sprague-Dawley rats were fed for 4 wk chow or a purified high-sucrose, high-fat (HSHF) diet that induced overt insulin resistance. Rats were fasted for 24 h and then refed chow for 1, 3, or 6 h. The postprandial rise in insulinemia was similar in both dietary cohorts, whereas glycemia was higher in HSHF-fed than in chow-fed animals, indicating glucose intolerance and insulin resistance. In chow-fed rats, adipose LPL activity increased two- to fourfold postprandially, but only minimally (30%) in HSHF-fed rats. Muscle LPL decreased postprandially in HSHF-fed rats, suggesting intact sensitivity to insulin, but it increased in chow-fed animals. Peak postprandial triglyceridemia was higher (+70%) in insulin-resistant than in control rats. The postprandial rate of appearance of triglycerides in the circulation was similar in control and insulin-resistant rats, indicating that hypertriglyceridemia of the latter was the result of impaired clearance. These results demonstrate that adipose LPL becomes resistant to insulin in diet-induced IR and further suggest that, under certain nutritional conditions, modifications in adipose LPL modulation associated with insulin resistance, along with low muscle LPL, heightens postprandial hypertriglyceridemia through attenuated triglyceride clearance.


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