Taurine supplementation prevents morpho-physiological alterations in high-fat diet mice pancreatic β-cells

High-fat diet aggravates glucose homeostasis disorder caused by chronic exposure to bisphenol A

Epidemiological findings on the association between bisphenol A (BPA, 2,2-bis-(4-hydroxyphenyl)propane) exposure and type 2 diabetes mellitus (T2DM) are paradoxical. In animal studies, BPA has been shown to disrupt pancreatic function and blood glucose homeostasis even at a reference 'safe' level during perinatal period. In this study, we explored the effects of long-term paternal exposure to a 'safe' level of BPA on parents themselves and their offspring. Adult male genitor rats fed with either standard chow diet (STD) or high-fat diet (HFD) were treated respectively with either vehicle or BPA (50 μg/kg per day) for 35 weeks. The male rats treated with vehicle or BPA for 21 weeks were then used as sires, and the adult female rats were fed with STD during the gestation and lactation. Offspring rats were weaned on postnatal day 21 and fed with STD in later life. Metabolic parameters were recorded on the adult male rats and their adult offspring. BPA exposure disrupted glucose homeostasis and pancreatic function, and HFD aggravated these adverse effects. However, BPA exposure did not alter body weight, body fat percentage, or serum lipid. In addition, the paternal BPA exposure did not cause adverse reproductive consequence or metabolic disorder in the adult offspring. Our findings indicate that chronic exposure to a predicted 'safe' dose of BPA contributes to glucose metabolic disorders, and that HFD aggravates these adverse effects in paternal rats.

Long-term intake of rice improves insulin sensitivity in mice fed a high-fat diet

OBJECTIVE

The aim of this study was to evaluate the effects of rice as a carbohydrate source and its molecular mechanisms on insulin resistance induced by a high-fat diet (HFD).

METHODS

C57 BL/6 J mice were divided into three groups and were fed a low-fat diet (LFD); a HFD (with 18% fat, 0.5% cholesterol, 51.5% w/w cornstarch and sucrose); or a HFD with rice (HFD-CR, with 18% fat, 0.5% cholesterol and 51.5% w/w rice powder) for 12 wk. In the HFD-CR diet, cooked rice powder was substituted for cornstarch and sucrose in the HFD as a carbohydrate source.

RESULTS

HFD-CR-fed mice had significantly lower body weight, blood glucose, insulin and leptin levels and ameliorated glucose responses with decreased homeostasis model assessment-insulin resistance compared with HFD-fed mice. Hepatic mRNA levels of phosphoenolpyruvate carboxykinase and glucose-6-phosphatase were down-regulated in the HFD-CR group. The hypertrophied islet size and the decreased pancreatic mRNA expression of glucose transporter 2 in the HFD group were normalized with cooked rice consumption. Rice promoted glucose uptake by activating AMP-activated protein kinase and downstream glucose transporter 4 in the skeletal muscle.

CONCLUSION

Rice consumption as a carbohydrate source might potentiate improvements in glucose uptake via AMP-activated protein kinase activation and glucose transporter 4 expression in the skeletal muscles, thereby improving insulin sensitivity.