Version 3 2024-06-18, 14:34Version 3 2024-06-18, 14:34
Version 2 2024-06-04, 03:33Version 2 2024-06-04, 03:33
Version 1 2019-05-02, 10:54Version 1 2019-05-02, 10:54
journal contribution
posted on 2024-06-18, 14:34authored byL Small, AE Brandon, BL Parker, V Deshpande, AF Samsudeen, Greg KowalskiGreg Kowalski, J Reznick, DL Wilks, E Preston, Clinton BruceClinton Bruce, DE James, N Turner, GJ Cooney
OBJECTIVE: Energy metabolism and insulin action follow a diurnal rhythm. It is therefore important that investigations into dysregulation of these pathways are relevant to the physiology of this diurnal rhythm. METHODS: We examined glucose uptake, markers of insulin action, and the phosphorylation of insulin signaling intermediates in muscle of chow and high fat, high sucrose (HFHS) diet-fed rats over the normal diurnal cycle. RESULTS: HFHS animals displayed hyperinsulinemia but had reduced systemic glucose disposal and lower muscle glucose uptake during the feeding period. Analysis of gene expression, enzyme activity, protein abundance and phosphorylation revealed a clear diurnal regulation of substrate oxidation pathways with no difference in Akt signaling in muscle. Transfection of a constitutively active Akt2 into the muscle of HFHS rats did not rescue diet-induced reductions in insulin-stimulated glucose uptake. CONCLUSIONS: These studies suggest that reduced glucose uptake in muscle during the diurnal cycle induced by short-term HFHS-feeding is not the result of reduced insulin signaling.