Biology subjects

Amaral, M. E.

Publications and source records attributed to Amaral, M. E..

2 recordsLinked to original sources

bioRxiv2023

Caloric restriction prevents inflammation and insulin dysfunction in middle-aged ovariectomized mice

Loss of ovarian function is associated with increased visceral fat. In this study, we aimed to study the effects of caloric restriction (CR) on metabolism in ovariectomized mice. Female, 8-12-month-old mice were divided into three groups: OVX (ovariectomized mice), OVXR (40% CR) and Sham. CR increased insulin sensitivity and glucose tolerance. AMPK phosphorylation was observed in the liver of OVXR mice. CR also increased hepatic cholesterol and triglyceride levels. The reductions in the level of TBARS in the serum and liver and of H2O2 in the liver of OVXR mice suggested alterations in the redox state of the liver. Although expression of catalase protein was reduced by CR, expression of superoxide dismutase was not altered by CR. Although interleukin IL-6 and IL-10 levels in OVXR mice were similar to those in Sham mice, macrophage infiltration was reduced in OVXR mice. OVXR mice had increased sirtuin1 levels and decreased sirtuin3 levels in the liver. In conclusion, CR improved the condition of ovariectomized mice by reducing adiposity and increasing insulin sensitivity and glucose tolerance through a mechanism that may involve AMPK.

physiology↗

bioRxiv2021

Quercetin prevents insulin dysfunction in hypertensive animals

Angiotensin II induced increase in hypertension enhances oxidative stress and compromises insulin action and pancreatic function. Quercetin-rich foods are beneficial for hypertensive and diabetic animals owing to their antioxidant function. The aim of this study was to evaluate the antioxidant effects of quercetin in hypertensive rats on insulin action, signaling, and secretion. Wistar rats were randomly divided into three groups: sham, hypertensive rats (H), and hypertensive rats supplemented with quercetin (HQ). After three months of initial hypertension, quercetin was administered at 50 mg/kg/day for 30 days. Our results indicate that hypertension and serum lipid peroxidation levels were reduced by quercetin supplementation. We observed increased insulin sensitivity in adipose tissue, corroborating the insulin tolerance test, HOMA index, and improvements in lipid profile. Despite normal insulin secretion at 2.8 and 20 mM of glucose, animals treated with quercetin exhibited increased number of islets per section; increased protein expression of muscarinic receptor type 3, VEGF, and catalase in islets; and hepatic mRNA levels of Ide were normalized. In conclusion, supplementation with quercetin improved insulin action and prevented pancreatic and metabolic dysfunction.

physiology↗