The Effect of Dietary Fat Load and Physical Exercise on the Flexibility and Partioning of Ectopic Lipids.
This study aims at assessing the effect of standardized dietary fat load and short-term aerobic exercise on systemic lipolysis, flexibility and partioning of ectopic fat stores (intramyocellular = IMCL, intrahepatocellular = IHCL, intramyocardial lipids = IMCaL) in relation to FFA in endurance trained athletes and hypopituitary patients compared to sedentary healthy control subjects.
Exercise is a powerful stimulation for growth hormone (GH) secretion in health. A standardised exercise test can, therefore, be discriminative for the diagnosis of GH-deficiency in adults. This will be assessed.
Hypothesis (ectopic fat stores)
- Ectopic fats stores are flexible fuel stores and are influenced by diet and physical activity.FFA availability may play an important regulatory role.
- There is a tissue specific partioning of triglycerides and/or FFA among non-adipose organs after fat load and physical exercise
- The flexibility of ectopic fat stores is related to insulin sensitivity
- Lipolytic and anti-lipolytic hormones are critical for regulating FFA availability (at rest or during exercise) and therefore also for the regulation of ectopic fat stores.
- GH is a lipolytica hormone. Lack of GH in adulthood is related to decreased FFA availability thereby influencing ectopic lipid stores Hypothesis diagnosis of GHD
- A short intensive physical exercise shows a good discriminative power to diagnose GHD.
Growth Hormone Deficiency
Dietary Supplement: Fat diet
Other: 2h standardized aerobic exercise
|Study Design:||Observational Model: Cohort
Time Perspective: Prospective
|Official Title:||The Effect of Dietary Fat Load and Physical Exercise on the Flexibility and Partioning of Ectopic Lipids.|
- Flexibility of IMCaL, IMCL and IHCL (fat load and exercise) [ Time Frame: Year 1 to 4 ] [ Designated as safety issue: No ]
- Determination of visceral fat mass by MRI [ Time Frame: Year 1 to 4 ] [ Designated as safety issue: No ]
- Determination of peripheral and hepatic insulin sensitivity by two step hyperinsulinemic euglycemic clamp [ Time Frame: Year 1 to 3 ] [ Designated as safety issue: No ]
- maximal exercise capacity [ Time Frame: Year 1 to 3 ] [ Designated as safety issue: No ]
|Study Start Date:||August 2011|
|Estimated Study Completion Date:||June 2015|
|Estimated Primary Completion Date:||June 2014 (Final data collection date for primary outcome measure)|
Endurance trained athletes: minimal >50 mlO2/KG body weight
Sedentary healthy control subjects: age, BMI, Gender and waist matched (to the growth hormone deficient patients)
GHD patients without a GH substitution therapy in the last 6 months
Dietary Supplement: Fat diet
Instructions for a high fat diet will be given at the end of visit 2. This consists of the usual food intake with a supplementary fat intake of 0.75g fat/kg BW, administered as 3 additional snacks. These snacks will be distributed in pre-packed bags. A food diary will be kept. All arms will receive this diet during the 3 days preceding the clamp.Other: 2h standardized aerobic exercise
Aerobic (50-60% of Vo2 max) standardized exercise on a bicycle during 2 hours
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|Department of Endocrinology, Diabetes and Clinical Nutrition, University Hospital Bern|
|Berne, Switzerland, 3010|
|Principal Investigator:||Emanuel Christ, Prof. Dr med. MD, PhD||Division of Endocrinology, Diabetes and Clinical Nutrition, University Hospital Bern|