Diurnal Testosterone Concentration

Study Overview
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Brief Summary
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In this case-controlled, observational study, 24 subjects will participate in a 12-hour blood collection with a single blood draw at +24 hours. 12 men will have low testosterone levels (hypogonadism) and 12 men will have normal testosterone levels. Blood samples will be drawn every 2 hours and later analyzed for total testosterone and calculated free testosterone. The primary objective of this study is to assess the degree of diurnal variation in men with testosterone deficiency.

Official Title
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Diurnal Testosterone Concentrations in Men With and Without Testosterone Deficiency

Conditions
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Testosterone Deficiency

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men with testosterone deficiency: Ability to read, write, and understand English Male sex at birth Age greater than or equal to 18 Age less than 46 Diagnosed with testosterone deficiency prior to visit 1 Screening testosterone concentration of less than 350 ng/dL Willing and able to comply with the study protocol Willing to provide informed consent for this study No previous exposure to exogenous T unless off therapy for at least 4 weeks Men without testosterone deficiency: Ability to read, write, and understand English Male sex at birth Age greater than or equal to 18 Age less than 46 Never diagnosed with testosterone deficiency Screening testosterone concentration of greater than 350 ng/dL Willing and able to comply with the study protocol Willing to provide informed consent for this study No previous exposure to exogenous T Exclusion Criteria: Previous exposure to exogenous T, clomiphene citrate, or other Selective Estrogen Receptor Modulators, unless off therapy for at least 4 weeks Serious psychiatric disease or uncontrolled medical illness, as suspected from the history or clinical examination Used any sex hormones or steroidal anabolic drug supplements within 28 days before screening testosterone collection Incapable of giving informed consent or complying with the protocol

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 46 Years

Sexes Eligible for Study
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Male

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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Men with testosterone deficiency<br>Screening testosterone concentration of less than 350 ng/dL | |
| Men without testosterone deficiency<br>Screening testosterone concentration of greater than 350 ng/dL | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in levels of serum total testosterone concentration | Blood samples analyzed by Beckman assays and equipment | 24 hours | 
| Change in levels of serum calculated free testosterone concentration | Blood samples analyzed by Beckman assays and equipment | 24 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in levels of estradiol | Blood samples analyzed by Beckman assays and equipment | 24 hours | 
| Change in levels of serum LH | Blood samples analyzed by Beckman assays and equipment | 24 hours | 
| Change in levels of serum FSH | Blood samples analyzed by Beckman assays and equipment | 24 hours | 
| Change in levels of serum SHBG | Blood samples analyzed by Beckman assays and equipment | 24 hours | 
| Change in levels of whole blood hematocrit | Blood samples analyzed by Quest assays and equipment | 24 hours |