Isao Morita

Effect of pre-exercise fructose ingestion on endurance performance in fed men

Twelve trained males, in a fed state, were studied to examine the effect of pre-exercise fructose ingestion on endurance capacity during prolonged cycling exercise. Sixty minutes prior to exercise, subjects ingested either 60 or 85 g fructose or a sweet placebo. Mean exercise intensity initially required 62% of the maximal aerobic power and thereafter increased to elicit 72 and 81% of maximal aerobic power at 90 and 120 min of exercise, respectively. Exercise time (mean +/- SE) to exhaustion was significantly increased after fructose ingestion, as compared to placebo ingestion (145 +/- 4 vs 132 +/- 3 min, P less than 0.01). During the exercise, no differences were observed between both trials for oxygen uptake, heart rate, or perceived exertion. Serum glucose and insulin levels between both trials were not significantly different throughout the experiment. There were also no significant differences in serum-free fatty acids and glycerol levels as well as respiratory exchange ratio between fructose and placebo trials during the exercise. The results suggest that fructose ingestion is of benefit before prolonged exercise, because it provides a carbohydrate source to contracting muscles without transient hypoglycemia and a depression of fat utilization, and thereby delays the fatigue.

Expression of mRNA for specific fibroblast growth factors associates with that of the myogenic markers MyoD and proliferating cell nuclear antigen in regenerating and overloaded rat plantaris muscle

Aim:  To examine the relations between specific fibroblast growth factors (FGFs) and satellite cell activation during muscle regeneration and hypertrophy in vivo, we measured mRNA expression of FGFs and myogenic markers in rat plantaris muscle after bupivacaine administration and synergist ablation.

The expression of IGF‐I and myostatin mRNAs in skeletal muscle of hypophysectomized and underfed rats during postnatal growth

Aim:  To determine the roles of myostatin and insulin‐like growth factor‐I (IGF‐I) during postnatal growth, we examined IGF‐I and myostatin mRNA expression in the skeletal muscles of hypophysectomized and underfed rats during postnatal growth.