Diurnal changes in glycogen stores in liver and skeletal muscle of rats in relation to the feed timing of sucrose.

Abstract

SummaryDiurnal changes in tissue glycogen stores were determined in rats in relation to the feed timing of sucrose. Rats were daily meal-fed on a 35% sucrose diet at 20.00-21.00 and a basal diet at 08.00-09.00, or meal-fed on the same diets at the reversed time for 7weeks. Half of the animals were allowed voluntary wheel-running between 21.00-08.00, but the remaining animals were restricted to exercise for 24h. At the end of the feeding period, both groups of rats were killed at 4-h intervals. Glycogen stores in liver and soleus muscle of sedentary rats showed sharp increases over 8h after the sucrose meal regardless of its feed timing. The increases continued for only 4h in exercised rats given the sucrose diet at the evening meal time. In contrast, glycogen stores in these tissues did notshow any noticeable increase after the basal diet regardless of its feed timing. Thus, the feeding of sucrose at the evening meal time seems to be more preferable than at the morning meal time in order to have higher glycogen stores in liver and skeletal muscle during the physically active phase of the day in rats. Diurnal changes of glycogen contents in heart and adipose tissue differed from those in liver and skeletal muscle.

Exercise Stimulates Pgc-1α Transcription in Skeletal Muscle through Activation of the p38 MAPK Pathway

“…Voluntary running has been employed in rodents as a model of exercise to induce skeletal muscle adaptation (30,45). Although the muscle activity pattern (intermittent bursts of activities) is different from human endurance exercise, such as long-distance running, the observed functional adaptations in skeletal muscle are similar between the animal models and humans in many aspects, which have been characterized in mouse skeletal muscle using various morphological and biochemical analyses (12,29,30).…”

Circadian regulation of metabolic homeostasis: causes and consequences

“…Interestingly, a diurnal rhythm in adipose tissue sensitivity to epinephrine-stimulated lipolysis is highest at the end of the active period in rats. 91 Norepinephrine also functions as an important neurotransmitter in the sympathetic nervous system and has central effects on feeding behavior; administration of hypothalamic norepinephrine suppresses feeding behavior in the dark phase and stimulates feeding behavior in the light phase of rats. 92 …”

Combined Light Exercise after Meal Intake Suppresses Postprandial Serum Triglyceride

“…In the previous studies, the effects of exercise, performed 8-16 h before (last day) meal intake on postprandial TG concentrations, have been examined; however, information regarding the effects of exercise on the day of a high-fat meal intake is limited, despite the importance of the timing of exercise and meal intake in gaining the benefits of exercise. Several studies have demonstrated that adequate meal timing on the day of exercise is important for glycogen loading, muscle building, and nutrient consumption (6,14,36), mainly due to the modification of hormone responses. The timing of exercise is therefore crucial to obtaining the maximum benefits of exercise and in the establishment of customized exercise programs for treating and preventing common diseases.…”