Effects of Testosterone and Fat Utilization

Study Overview
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Brief Summary
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Evidence is accumulating that there are sex differences in energy and substrate metabolism. The positive or negative consequences of such metabolic differences between men and women need to be evaluated with respect to health outcomes. The importance of aberrant lipid metabolism in metabolic diseases such as obesity, diabetes and cardiovascular disease, makes understanding the distinction between normal vs aberrant critical to future treatment and prevention strategies. Sex differences in the effects of catecholamines on lipid metabolism and substrate oxidation in non-obese, healthy individuals, have been consistently observed. In addition, distinct differences in men and women exist in the distribution of body fat, with men typically having greater central adiposity than women. Accumulation of fat in the abdomen is associated with an increased risk for metabolic abnormalities such as hyperlipidemia and insulin resistance. In the current study, therefore, the role of testosterone in determining the sex differences in catecholamine mediated substrate metabolism and deposition of dietary fat into upper versus lower body adipose tissue depots will be addressed.

Official Title
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Testosterone Effects on Systemic Lipolysis and Whole Body Lipid Utilization

Conditions
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Healthy, Volunteers

Intervention / Treatment
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* Drug: GnRH antagonist
* Drug: Aromatase Inhibitors
* Drug: Testosterone gel


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: normal weight (BMI of 23-29.9 kg/m2) not be highly trained (< 5hrs of moderate intensity, planned exercise per week). Exclusion Criteria: Patients will be excluded if they have one or more of the following out-of-range values measured on a fasting blood sample: glucose <65 or > 110 mg/dl, insulin > 20 uU/ml, thyroid stimulating hormone <0.5 or >5.0 uU/ml, growth hormone >2.5 ng/ml. Subjects who may be: anemic (hemoglobin < 14.5 g/dl men ), have abnormal liver function tests: alanine amino transferase > 47 U/l, aspartate aminotransferase, > 47 U/l, alkaline phosphatase <39 or >117 U/l) or creatinine (<0.6 or >1.1 mg/dl).

Ages Eligible for Study
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Minimum Age: 25 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: Control<br> | |
| Placebo Comparator: GnRH antagonist + Placebo Gel<br> | Drug: GnRH antagonist<br> <br> Drug: Aromatase Inhibitors<br> <br> |
| Active Comparator: GnRH antagonist + Testosterone Gel<br> | Drug: GnRH antagonist<br> <br> Drug: Aromatase Inhibitors<br> <br> Drug: Testosterone gel<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Dietary fat tracer for storage of meal derived fatty acids | 50 uCi of [1-14C] oleic acid administered with an inpatient test meal | 4 weeks |