Tucum-do-cerrado (Bactris setosa Mart.) may enhance hepatic glucose response by suppressing gluconeogenesis and upregulating Slc2a2 via AMPK pathway, even in a moderate iron supplementation condition

Dietary phytochemicals may improve glucose metabolism while iron excess seems to be associated to impaired glucose homeostasis and insulin responses. This study investigated the effect of tucum-do-cerrado (Bactris setosa Mart.) consumption on the carbohydrate metabolism and redox response in rats supplemented or not with dietary iron. Male wistar rats were treated with one of the following diets: CT: control diet (AIN- 93G); +Fe: iron-enriched diet; Tuc: control diet +15% tucum-do-cerrado or Tuc + Fe: iron-enriched diet +15% tucum-do-cerrado. Iron supplementation increased muscle lipid and protein oxidation, hepatic glucokinase (GK) and phosphofrutokinase 1 (PFK1) activities and decreased hepatic glucose-6-phosphatase (G6Pase), intestinal Scl2a2 and muscle Slc2a4 and Prkaa2α mRNA levels compared to CT group. Tucum-do-cerrado consumption (Tuc) increased hepatic Slc2a2, Prkaa1α, Prkaa2α and intestinal Slc5a1 mRNA levels, also decreased hepatic G6Pase activity, muscle Slc2a4 and Prkaa2α in relation to CT group. The association of tucum-do-cerrado with iron-enriched diet increased hepatic Prkaa1 and Pck1 compared to the CT and + Fe groups, intestinal Slc2a2 mRNA levels compared to the +Fe group, while decreased hepatic G6Pase activity in relation to the CT, +Fe and Tuc + Fe groups and muscle Slc2a4 and Prkaa2α compared to CT group. These results suggest that tucum-do-cerrado consumption might induce Prkaa1α and Prkaa2α expression, which may inhibit gluconeogenic rate limiting enzyme, G6Pase, and upregulates GLUT2 hepatic glucose uptake. In addition, moderate iron supplementation improves intracellular hepatic glucose response, stimulating the glycolytic rate limiting enzymes GK and PFK1 while inhibiting gluconeogenic enzyme G6Pase.