Additive insulinogenic action of Opuntia ficus-indica cladode and fruit skin extract and leucine after exercise in healthy males.

Background: Oral intake of a specific extract of Opuntia ficus-indica cladode and fruit skin (OpunDia™) (OFI) has been shown to increase serum insulin concentration while reducing blood glucose level for a given amount of glucose ingestion after an endurance exercise bout in healthy young volunteers. However, it is unknown whether OFI-induced insulin stimulation after exercise is of the same magnitude than the stimulation by other insulinogenic agents like leucine as well as whether OFI can interact with those agents. Therefore, the aims of the present study were: 1) to compare the degree of insulin stimulation by OFI with the effect of leucine administration; 2) to determine whether OFI and leucine have an additive action on insulin stimulation post-exercise.

Sprint interval training in hypoxia stimulates glycolytic enzyme activity.

Purpose: In this study, we compared the effect of sprint interval training (SIT) in normoxia versus hypoxia on muscle glycolytic and oxidative capacity, monocarboxylate transporter content, and endurance exercise performance.

Methods: Healthy male volunteers (18-30 yr) performed 6 wk of SIT on a cycling ergometer (30-s sprints vs 4.5-min rest intervals; 3 d · wk(-1)) in either normobaric hypoxia (HYP, FiO2 = 14.

Opuntia ficus-indica ingestion stimulates peripheral disposal of oral glucose before and after exercise in healthy men.

The purpose of this study was to investigate the effect of Opuntia ficus-indica (OFI) cladode and fruit-skin extract on blood glucose and plasma insulin increments due to high-dose carbohydrate ingestion, before and after exercise. Healthy, physically active men (n = 6; 21.0 ± 1.

High-fat diet overrules the effects of training on fiber-specific intramyocellular lipid utilization during exercise.

In this study, we compared the effects of endurance training in the fasted state (F) vs. the fed state [ample carbohydrate intake (CHO)] on exercise-induced intramyocellular lipid (IMCL) and glycogen utilization during a 6-wk period of a hypercaloric (∼+30% kcal/day) fat-rich diet (HFD; 50% of kcal). Healthy male volunteers (18-25 yrs) received a HFD in conjunction with endurance training (four times, 60-90 min/wk) either in F (n = 10) or with CHO before and during exercise sessions (n = 10).

Exercise-induced, but not creatine-induced, decrease in intramyocellular lipid content improves insulin sensitivity in rats.

The effect of creatine supplementation, alone or in combination with exercise training, on insulin sensitivity, intramyocellular lipid content (IMCL) and fatty acid translocase (FAT)/CD36 content was investigated in rats fed a sucrose-rich cafeteria diet during 12 weeks. Five experimental conditions were CON, receiving normal pellets; CAF, fed the cafeteria diet; CAF(TR), fed the cafeteria diet together with exercise training in weeks 8-12 and CAF(CR) and CAF(CRT) that were analogous to CAF and CAF(TR), respectively, but which received daily 2.5% of creatine monohydrate.

The unfolded protein response in human skeletal muscle is not involved in the onset of glucose tolerance impairment induced by a fat-rich diet.

Endoplasmic reticulum (ER) stress in pancreas, liver, and adipose tissue is a key event in the pathogenesis of obesity-related metabolic disease. Lipid-induced ER stress in liver and adipose tissue leads to inhibition of insulin signaling. Whether this mechanism exists in skeletal muscle is currently unknown.

Beneficial metabolic adaptations due to endurance exercise training in the fasted state.

Training with limited carbohydrate availability can stimulate adaptations in muscle cells to facilitate energy production via fat oxidation. Here we investigated the effect of consistent training in the fasted state, vs. training in the fed state, on muscle metabolism and substrate selection during fasted exercise.

Training in the fasted state improves glucose tolerance during fat-rich diet.

A fat-rich energy-dense diet is an important cause of insulin resistance. Stimulation of fat turnover in muscle cells during dietary fat challenge may contribute to maintenance of insulin sensitivity. Exercise in the fasted state markedly stimulates energy provision via fat oxidation.

Beta-alanine improves sprint performance in endurance cycling.

Purpose: Recent research has shown that chronic dietary beta-alanine (betaALA) supplementation increases muscle carnosine content, which is associated with better performance in short (1-2 min) maximal exercise. Success in endurance competitions often depends on a final sprint. However, whether betaALA can be ergogenic in sprint performance at the end of an endurance competition is at present unknown.

Androgen signaling in myocytes contributes to the maintenance of muscle mass and fiber type regulation but not to muscle strength or fatigue.

Muscle frailty is considered a major cause of disability in the elderly and chronically ill. However, the exact role of androgen receptor (AR) signaling in muscle remains unclear. Therefore, a postmitotic myocyte-specific AR knockout (mARKO) mouse model was created and investigated together with a mouse model with ubiquitous AR deletion.