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Testosterone-Driven Growth-Hormone (GH) Secretion in Aging Men

Sponsor
Mayo Clinic (Other)
Overall Status
Completed
CT.gov ID
NCT00309855
Collaborator
GlaxoSmithKline (Industry)
80
Enrollment
1
Location
4
Arms
32
Duration (Months)
2.5
Patients Per Site Per Month

Study Details

Study Description

Brief Summary

This study is being done to understand how testosterone, the major male sex hormone, controls the pituitary gland's secretion of growth hormone (GH). GH is an important metabolic hormone, which controls sugar; fat and protein use in the body and maintains muscle strength and bone calcium content. Both testosterone and GH decline in older men. The age-related fall in these hormones probably contributes to relative frailty, reduced quality of life, bone loss, muscle wasting and impaired sexual function.

Condition or Disease Intervention/Treatment Phase
Phase 1

Detailed Description

Repletion of testosterone in older men drives pulsatile GH secretion via conjoint facilitation of feedforward by the primary secretagogues GHRH and GHRP and repression of feedback by the dominant inhibitor, somatostatin; and, in corollary, testosterone acts via aromatization to estradiol and/or reduction to 5 alpha-dihydrotestosterone

Study Design

Study Type:
Interventional
Actual Enrollment :
80 participants
Allocation:
Randomized
Intervention Model:
Crossover Assignment
Masking:
Double (Participant, Investigator)
Primary Purpose:
Basic Science
Official Title:
Mechanisms of Testosterone-Driven Growth-Hormone (GH) Secretion in Aging Men: Modulation of GHRH, GHRP and Somatostatin Action by Estrogenic Versus Androgenic Steroids
Study Start Date :
Dec 1, 2005
Actual Primary Completion Date :
Aug 1, 2008
Actual Study Completion Date :
Aug 1, 2008

Arms and Interventions

Arm Intervention/Treatment
Placebo Comparator: Double Placebo

(i.m. vehicle 0.5 mL weekly x three injections and oral placebo once daily x 21 days)

Drug: Placebo
im and orally
Other: Testosterone IM and oral placebo

IM injections weekly x three injections and oral placebo once daily x 21 days

Drug: Testosterone
injections
Other: Testosterone and Oral Anastrozole

IM injections weekly x 3 injections and oral daily x 21 days

Drug: Testosterone
injections

Drug: Anastrazole
orally x 21 days
Other: Testosterone and Dutasteride

IM injections weekly x 3 injections and oral once daily x 21 days

Drug: Testosterone
injections

Drug: Dutasteride
orally x 21 days

Outcome Measures

Primary Outcome Measures

  1. Growth Hormone concentration after injections [24 days]

    GH will be measured 4 different times mornings within 16-21 days following the first testosterone injection (day 1).

Eligibility Criteria

Criteria

Ages Eligible for Study:
50 Years to 80 Years
Sexes Eligible for Study:
Male
Accepts Healthy Volunteers:
Yes
Inclusion Criteria:

  • healthy men between the ages of 50 and 80;

  • normal weight (within 30% of ideal body weight defined by New York Metropolitan Life tables); and

  • normal hematocrit (greater than 38%);

  • community dwelling; and

  • voluntarily consenting

Exclusion Criteria:

  • recent use of psychotropic or neuroactive drugs (within five biological half-live);

  • obesity (outside weight range above);

  • anemia (hematocrit < 38%);

  • drug or alcohol abuse, psychosis, depression, mania or severe anxiety;

  • acute or chronic organ-system disease;

  • endocrinopathy, other than primary thyroidal failure receiving replacement;

  • nightshift work or recent transmeridian travel (exceeding 3 time zones within 7 days of admission);

  • acute weight change (loss or gain of > 2 kg in 6 weeks);

  • allergy to administered compounds; and

  • unwillingness to provide written informed consent.

Contacts and Locations

Locations

Site City State Country Postal Code
1 Mayo Clinic Rochester Minnesota United States 55905

Sponsors and Collaborators

  • Mayo Clinic
  • GlaxoSmithKline

Investigators

  • Principal Investigator: Johannes D. Veldhuis, M.D., Mayo Clinic

Study Documents (Full-Text)

None provided.

More Information

Publications

None provided.
Responsible Party:
, ,
ClinicalTrials.gov Identifier:
NCT00309855
Other Study ID Numbers:
  • 319-03
First Posted:
Apr 3, 2006
Last Update Posted:
Jul 31, 2012
Last Verified:
Jul 1, 2012
Additional relevant MeSH terms:
Anastrozole
Testosterone
Dutasteride

Study Results

No Results Posted as of Jul 31, 2012