Proceedings of The Physiological Society

Europhysiology 2018 (London, UK) (2018) Proc Physiol Soc 41, PCB210

Poster Communications

The effects of quercetin and fenofibrate supplementation on serum insulin and adiponectin levels in male Sprague Dawley rats fed a high fructose diet, post-weaning

J. Donaldson1, M. C. Molopo1, K. Erlwanger1

1. Faculty of Health Sciences, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa.

Fructose-rich diets are implicated in obesity and Type II diabetes development, associated with insulin resistance and metabolic syndrome (MetS). Insulin and adiponectin are important in energy metabolism. Hypoadiponectinemia associated with obesity is central to insulin resistance, Type II diabetes and MetS development. Increased adiponectin levels are protective against MetS as a result of its' anti-inflammatory, antidiabetic and cardioprotective effects. Phytotherapies are being investigated for treatment of risk factors associated with MetS. Quercetin, a flavonoid abundant in fruits and vegetables, decreases insulin and increases adiponectin levels in animal models of fructose-induced MetS, improving the insulin resistance and pro-inflammatory status associated with MetS. Quercetin is usually administered to adult rats as a form of treatment for MetS, not as a preventative measure. We investigated the effects of quercetin on serum insulin and adiponectin levels of growing male Sprague Dawley rats fed a high fructose diet, post weaning. Thirty-eight, male rats (21 days old) were randomly divided into five groups. Group 1 (n = 8) received normal rat chow (NRC), plain gelatine cubes (GC) and tap water (TW); Group 2 (n = 8) received NRC, GC with quercetin (100 mg/kg body mass daily) and TW; Group 3 (n = 8) received NRC, plain GC and a 20% fructose solution (FS); Group 4 (n = 7) received NRC, GC with quercetin (100 mg/kg body mass daily) and a 20% FS; Group 5 (n = 7) received NRC, GC with fenofibrate (100 mg/kg body mass daily) and a 20% FS. Rats were fed ad libitum for ten weeks after which blood samples were collected. Serum insulin and adiponectin levels were determined using ELISA. Values are means ± SD, compared using ANOVA. Insulin levels were significantly increased (p < 0.0001) in rats receiving fructose only (Group 3: 4.8±1.2 vs Group 1: 2.2±1.0 and Group 2: 2.9±1.0 This increase was not prevented by the administration of quercetin (Group 4: 5.0±0.6 or fenofibrate (Group 5: 5.7±0.7, together with the fructose. Inclusion of quercetin in the diets of the rats receiving fructose resulted in significantly increased (p < 0.01) adiponectin levels (Group 4: 102.8±20.5 compared to the negative control groups (Group 1: 26.0±6.4; Group 2: 42.0±19.1, however the adiponectin levels were not significantly different (p > 0.05) to the rats receiving fructose only (Group 3: 72.1±24.0 Adiponectin levels were significantly increased (p < 0.01) in the group receiving fructose and fenofibrate (Group 5: 169.3±66.3 compared to all other treatment groups. In the fructose-fed rats, that are prone to metabolic dysfunction, the increase in adiponectin levels observed following fenofibrate administration could result in protective effects in the rats with regards to metabolism. However, this effect was not as pronounced in the rats receiving quercetin together with fructose.

Where applicable, experiments conform with Society ethical requirements