Physical exercise reduces pyruvate carboxylase (PCB) and contributes to hyperglycemia reduction in obese mice

Abstract

The present study evaluated the effects of exercise training on pyruvate carboxylase protein (PCB) levels in hepatic tissue and glucose homeostasis control in obese mice. Swiss mice were distributed into three groups: control mice (CTL), fed a standard rodent chow; diet-induced obesity (DIO), fed an obesity-inducing diet; and a third group, which also received an obesity-inducing diet, but was subjected to an exercise training protocol (DIO + EXE). Protocol training was carried out for 1 h/d, 5 d/wk, for 8 weeks, performed at an intensity of 60% of exhaustion velocity. An insulin tolerance test (ITT) was performed in the last experimental week. Twenty-four hours after the last physical exercise session, the animals were euthanized and the liver was harvested for molecular analysis. Firstly, DIO mice showed increased epididymal fat and serum glucose and these results were accompanied by increased PCB and decreased p-Akt in hepatic tissue. On the other hand, physical exercise was able to increase the performance of the mice and attenuate PCB levels and hyperglycemia in DIO + EXE mice. The above findings show that physical exercise seems to be able to regulate hyperglycemia in obese mice, suggesting the participation of PCB, which was enhanced in the obese condition and attenuated after a treadmill running protocol. This is the first study to be aimed at the role of exercise training in hepatic PCB levels, which may be a novel mechanism that can collaborate to reduce the development of hyperglycemia and type 2 diabetes in DIO mice.

Short-term Resistance Training Increases APPL1 Content in the Liver and the Insulin Sensitivity of Mice Fed a Long-term High-fat Diet

“…The standard diet (NUVILAB ® ) consisted of 5 g of fat derived from soybean oil, 22 g of protein, and 51.5 g of carbohydrates per 100 g of diet (339 Kcal). The HFD consisted of 35.8 g of fat derived from coconut oil, 23 g of protein, and 34.5 g of carbohydrates (552.2 Kcal) as previously described [20]. The Swiss mice were random distributed to the following groups: (i) mice fed a chow diet for 16 months (group CTR) (n = 4); (ii): Mice fed an HFD for 16 months (group HFD) (n = 4); (iii) Mice fed an HFD for 16 months and subjected to the RT protocol (group HFD-EXE ) (n = 4) (▶Fig.…”

Acute physical exercise increases APPL1/PI3K signaling in the hypothalamus of lean mice

“…The adipose mass was collected and weighed on the analytical balance. The brain was removed, and the hypothalamus was collected (Rodrigues et al., ; Ropelle et al., ) and homogenized in extraction buffer as previously described (Muñoz et al., ). The homogenate was used for the total protein content determination by the bicinchoninic acid (BCA) method (Sigma‐Aldrich ® ), while another part was subjected to Western blotting (WB) with specific antibodies.…”

Exercise decreases CLK2 in the liver of obese mice and prevents hepatic fat accumulation

“…After 24 h of the last chronic exercise session and 16 weeks of treatment, the ITT was performed after a fasting period of 6 h. After the measurement of fasting glycemia (t0 '), 1.5 U/kg insulin (Humulin R; Lilly, Indianapolis, IN) was injected intraperitoneally, and blood samples were collected through the tail at 5, 10, 15, 20, 25, and 30 min after the insulin stimulation to determine circulating glucose levels. The kITT was calculated as previously described . The glycemia was measured by a glucometer (Accu‐Chek; Roche Diagnostics).…”

“…On the other hand, the high-fat diet (HFD) consisted of 35.8 g of fat derived from coconut oil, 23 g of protein, and 34.5 g of carbohydrates (552.2 Kcal) as previously described. 11 The animals were distributed to the following groups: (i) Lean: fed with standard diet and sedentary (n = 10); (ii) Obese: fed with HFD for 16 weeks and sedentary (n = 10); (iii) Trained Obese: fed with HFD for 16 weeks with initiation of the chronic exercise protocol after the 8th week of dietary exposure (n = 10). Physiological tests were carried out with part of each group (n = 7), and these same animals were used for both molecular (n = 4-5) and histological analyzes (n = 5).…”