Effect of a meal feeding schedule on hepatic glycogen synthesis and gluconeogenesis in rats

Abstract

We investigated the effect of a meal feeding schedule (MFS) on food intake, hepatic glycogen synthesis, hepatic capacity to produce glucose and glycemia in rats. The MFS comprised free access to food for a 2-hour period daily at a fixed mealtime (8.00-10.00 a.m.) for 13 days. The control group was composed of rats with free access to food from day 1 to 12, which were then starved for 22 h, refed with a single meal at 8.00-10.00 a.m. and starved again for another 22 h. All experiments were performed at the meal time (i.e. 8.00 a.m.). The MFS group exhibited increased food intake and higher glycogen synthase activity. Since gluconeogenesis from L-glutamine or L-alanine was not affected by MFS, we conclude that the increased food intake and higher glycogen synthase activity contributed to the better glucose maintenance showed by MFS rats at the fixed meal time.

Blood glucose regulation during fasting in rats under food restriction since birth

“…Thus, considering that gluconeogenesis is a metabolic pathway with high energetic cost, it could be suggested that the preference for glycogenolysis could be an adaptation for glycemia maintenance during fasting to overcome the lower food availability (Batista et al, 2001;Bazotte et al, 2000). In conformity with this suggestion, fasting glycemia did not differ (P > 0.05) between CG (97.3±23.3 mg/dL) and RG groups (103.3±25.9 mg/dL).…”

“…Considering that the glucose production before L-Ala infusion resulted from glycogen (Batista et al, 2001), it could be inferred that the livers from RG showed a higher rate of glycogenolysis despite the fact that the hepatic glycogen content was not significantly different between the groups. In contrast, lower (P < 0.05) liver production of glucose and L-lactate during the infusion of L-Ala was observed.…”

“…However, in rats, undernutrition caused by food restriction since birth has marked effects on body weight development, accompanied by reduction in the muscle mass and fat stores (Mazeti and Furlan, 2008;Vismara and Furlan, 2007). Several studies have demonstrated changes in the liver metabolism in adult rats submitted to food restriction (Batista et al, 2001;Bazotte et al, 1989Bazotte et al, , 2000. These alterations include changes in liver gluconeogenesis, nitrogen removal, and activation of the transaminases (Dhahbi et al, 1999;Hagopian et al, 2003;Spindler, 2001).…”

Biomedical vignette

“…Using the liver perfusion technique, Batista et al [1] investigated the hepatic glycogen synthesis and gluconeogenesis from alanine and glutamine in meal-fed trained rats. Using the liver perfusion technique, Batista et al [1] investigated the hepatic glycogen synthesis and gluconeogenesis from alanine and glutamine in meal-fed trained rats.…”

Biomedical Vignette

“…Using the liver perfusion technique, Batista et al [1] investigated the hepatic glycogen synthesis and gluconeogenesis from alanine and glutamine in meal-fed trained rats. They showed that meal-fed training increases the activity of hepatic glycogen synthase.…”