How is Glycogen Supercompensation Regulated in Human Skeletal Muscle

NCT ID: NCT03458741

Last Updated: 2018-03-08

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 9 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2013-09-05
• Study Completion Date: 2014-12-31

Brief Summary

Nine healthy, moderately fit male volunteers participated in the study. The subjects gave written informed consent after having been informed of any possible risk and discomfort associated with the study. The study was approved by the regional ethics committee in Denmark (Journal number: H-4-2013-071) and performed in accordance with the Declarations of Helsinki II.

All subjects underwent 3 clinical investigations (day 1, day 2 and day 5) during a 5 day glycogen supercompensation regime. The subjects were asked to refrain from physical activity and to eat a controlled diet containing 60% carbohydrates (CHO) for 4 days prior to the initial experiments.

Upon arrival at the laboratory on day 1, the subjects performed one-legged knee extensor exercise for 1 hour at 80% of PWL interspersed by 5 min bouts at 90% of PWL. This was followed by interval exercise until exhaustion containing 4 min bouts starting at 100% PWL followed by 1 min at 50% of PWL. Upon cessation of exercise the subjects showered and rested in the supine position for 4 hours. Then a 120 min hyperinsulinemic euglycemic clamp was initiated by a bolus insulin injection (9.0 mU/kg, Actrapid, Novo Nordisk, Denmark) followed by continuous insulin infusion (1.42 mU/kg/min insulin) reaching a level of plasma insulin around 100 µU/mL (n=9). At least 2 hours before the insulin clamp, catheters were placed in both femoral, one antecubital and one dorsal hand vein. A heat pad was placed around the lower part of the arm and hand in order to "arterialize" blood drawn from the hand vein. Substrate uptake/release across the legs was calculated by multiplying the arterial-venous (AV) difference in blood substrate concentration by femoral arterial blood flow (measured by ultrasound, Philips DICOM). Blood glucose levels were maintained at the euglycemic predefined target by continuously adjusting the glucose infusion rate (GIR) (20% glucose solution; Fresenius Kabi, Sweden). Concurrent measures of substrate AV differences and blood flow were performed every 20 min. Muscle biopsies from m. vastus lateralis were obtained under local anaesthesia (3-5 ml of Xylocaine, 20 mg/ml.) in the basal- and insulin-stimulated state (120 min) by use of needle biopsy technique. Muscle specimen were frozen within 20 sec in liquid nitrogen and stored at -80°C for further analysis. A new incision was made for every biopsy and spaced 4-5 cm apart.

This insulin clamp procedure in combination with basal and insulin stimulated muscle biopsies was repeated in the rested state (without prior exercise) on day 2 and day 5. The subjects arrived in the morning in the overnight fasted state at day 1, day 2 and day 5. During the 5 day supercompensation regime the subjects were provided a predefined isocaloric diet containing 80% carbohydrates, 10% fat and 10% proteins. All food items were handle out to the subjects and compliance of the diet regime was ensured by survey.

Conditions

Glycogen Depletion; Insulin Sensitivity

Study Design

• Intervention Model: SEQUENTIAL
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: NONE

Interventions

Glycogen Supercompensation

The subjects arrived in the morning in the overnight fasted state at day 1, day 2 and day 5. Upon arrival in the morning the subjects were given a meal corresponding to 5% of their daily energy intake (\~600-800 kJ). During the 5 day supercompensation regime the subjects were provided a predefined isocaloric diet containing 80% carbohydrates, 10% fat and 10% proteins. All food items were handle out to the subjects and compliance of the diet regime was ensured by survey.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• male
• BMI between BMI 20-25 kg/m2
• healthy and not using medication
• not smoking
• habitual physical activity level of 2 - 6 hours pr. week
• no incidence of diabetes, cardiovascular disease or other metabolic diseases in close family

Exclusion Criteria

• female
• BMI below 20 and above 25 kg/m2
• using medication
• smoking
• habitual physical activity level below 2 h pr. week or above 6 hours pr. week
• incidence of diabetes, cardiovascular disease or metabolic disease in close family

• Minimum Eligible Age: 25 Years
• Maximum Eligible Age: 30 Years
• Eligible Sex: MALE
• Accepts Healthy Volunteers: Yes

Sponsors

University of Copenhagen

OTHER

Sponsor Role: lead

Responsible Party

Janne Rasmuss Hingst

PhD

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

Department of Nutrition, Exercise and Sports

Copenhagen, Capital Region, Denmark

Countries

Denmark

Other Identifiers

Supercomp

Identifier Type: -

Identifier Source: org_study_id