Substrate Utilization and Hormonal Status in Women

Completed

• Conditions: Substrate Utilization

• Registration Number: NCT01095614
• Lead Sponsor: University Hospital, Clermont-Ferrand

Brief Summary

Women sexual hormones (i.e. estrogen) are involved in the regulation of substrate utilization and storage. Being under oral contraception (OC) may conduct to metabolic and hormonal modifications, but results are confused regarding the impact on substrate utilization. In the present study, the aim is then to explore the effect of hormonal status on substrate utilization during sous-maximal exercise, comparing women with and without OC.

We hypothesised that women under OC have a lower Respiratory Exchange Ratio (RER) at exercise than women without contraception underlying a greater reliance on fat oxidation.

Detailed Description

24 healthy young women (12 with OC and 12 without any contraception) will complete a maximal test on an ergometer cycle to obtain their maximal oxygen consumption (VO2max).Their body composition will be assessed by DXA. They will be asked to complete 3 experimental sessions.

During a first session the volunteers will remain inactive, and only a breakfast will be offered. During the second session, a breakfast will be offered and they will have to complete a sub-maximal exercise set at 60% of their VO2max 3 hours after breakfast. And the third session will consist in the realisation of exercise on fast state. Those three sessions will be realized in a randomized order. Several blood (catheter) and salivary samples will be collected during the three sessions, throughout the experimental day.

Study Timeline

• Study Start: 2010-02
• Study First Submitted: 2010-02-16
• Study First Submitted QC: 2010-03-29
• Study First Posted: 2010-03-30
• Primary Completion: 2010-11
• Study Completion: 2010-11
• Status Verified: 2011-01
• Last Update Submitted: 2011-01-18
• Last Update Posted: 2011-01-19

Recruitment & Eligibility

• Status: COMPLETED
• Sex: Female
• Target Recruitment: 24

Inclusion Criteria

• Female
• Adults between 19 to 30 years old
• Body mass index between 20 and 25 kg.m-²
• Oral contraception (half of the sample) : mini-dosed, and mono-phasic, ethinyl estradiol ≤ 30 µg
• Without contraception (half of the sample)
• Affiliated to National Health Insurance
• Subject giving her written informed consent
• Subject considered as normal after clinical examination and medical questionnaire.

Exclusion Criteria

• Chronic pathologies : cardiovascular diseases, cancer, chronic inflammation diseases, renal, intestinal impairments
• Refusal to be registered on the National Volunteers Data file
• Being in exclusion on the National Volunteers Data file
• Practising intensive physical exercise
• Heavy consumer of alcohol or/and tobacco
• Previous medical and/or surgery judged by the investigator as incompatible with this study
• Pregnancy

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Substrate utilization will be the main outcome under study.For each volunteer, it will be assessed during exercise (between 12h and 12h45) for the 2 experimental conditions with exercise	during exercise (between 12h and 12h45)	Substrate utilization: The Respiratory Exchange Ratio (RER) that corresponds to carbon dioxide production divided by oxygen consumption (VCO2/VO2) will be used to determine the energetic substrate used during exercise. This RER will be obtained, in continuous, thanks to an indirect calorimetric system composed of a breath by breath gas analyzer. A RER closed to 0.7 illustrates lipid utilization while carbohydrate use will correspond to a RER that reached 1.

Secondary Outcome Measures

Name	Time	Method
The hormonal regulation involved in substrate utilization. It will be assessed during the 3 experimental conditions during all the experimental day: - Breakfast + exercise - Exercise alone - Breakfast alone	before (8h, 8h45), during (12h, 12h20, 12h30, 12h45) and after exercise (13h15, 13h45; 14h45)	The hormonal regulations involved in the substrate utilization will be assessed thanks to blood samples collected before, during and after exercise.; At each blood collection, the nurses will collect a EDTA tube (5ml) used to assess free fatty acid and glycerol; and 2 heparin ones (2\*5ml) to assess 17β-œstradiol, progesterone, triglycerides, cholesterol, HDL-C, LDL-C, glucose, insulin, growth hormone, IGF-I, IGFBP-1, IGFBP-3, adrenaline, noradrenaline, Atrial Natriuretic Peptide, and C-Reactive Protein.

Trial Locations

Locations (1)

CHU Clermont-Ferrand; 🇫🇷 Clermont-Ferrand, France