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

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00309855
Recruitment Status : Completed
First Posted : April 3, 2006
Last Update Posted : July 31, 2012
Information provided by:
Mayo Clinic

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
Aging Drug: Placebo Drug: Testosterone Drug: Anastrazole Drug: Dutasteride 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 Type : Interventional  (Clinical Trial)
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 : December 2005
Actual Primary Completion Date : August 2008
Actual Study Completion Date : August 2008

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Hormones
U.S. FDA Resources

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
Testosterone IM and oral placebo
IM injections weekly x three injections and oral placebo once daily x 21 days
Drug: Testosterone
Testosterone and Oral Anastrozole
IM injections weekly x 3 injections and oral daily x 21 days
Drug: Testosterone
Drug: Anastrazole
orally x 21 days
Testosterone and Dutasteride
IM injections weekly x 3 injections and oral once daily x 21 days
Drug: Testosterone
Drug: Dutasteride
orally x 21 days

Primary Outcome Measures :
  1. Growth Hormone concentration after injections [ Time Frame: 24 days ]
    GH will be measured 4 different times mornings within 16-21 days following the first testosterone injection (day 1).

Information from the National Library of Medicine

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Ages Eligible for Study:   50 Years to 80 Years   (Adult, Senior)
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.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00309855

United States, Minnesota
Mayo Clinic
Rochester, Minnesota, United States, 55905
Sponsors and Collaborators
Mayo Clinic
Principal Investigator: Johannes D. Veldhuis, M.D. Mayo Clinic

Responsible Party: Johannes D. Veldhuis, M.D., Mayo Clinic Identifier: NCT00309855     History of Changes
Other Study ID Numbers: 319-03
First Posted: April 3, 2006    Key Record Dates
Last Update Posted: July 31, 2012
Last Verified: July 2012

Additional relevant MeSH terms:
Testosterone enanthate
Testosterone undecanoate
Testosterone 17 beta-cypionate
Hormones, Hormone Substitutes, and Hormone Antagonists
Physiological Effects of Drugs
Antineoplastic Agents, Hormonal
Antineoplastic Agents
Anabolic Agents
5-alpha Reductase Inhibitors
Steroid Synthesis Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Hormone Antagonists
Aromatase Inhibitors
Estrogen Antagonists