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

This study has been completed.
Information provided by:
Mayo Clinic Identifier:
First received: March 31, 2006
Last updated: July 27, 2012
Last verified: July 2012
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 Intervention Phase
Aging Drug: Placebo Drug: Testosterone Drug: Anastrazole Drug: Dutasteride Phase 1

Study Type: Interventional
Study Design: 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

Resource links provided by NLM:

Further study details as provided by Mayo Clinic:

Primary Outcome Measures:
  • 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).

Enrollment: 80
Study Start Date: December 2005
Study Completion Date: August 2008
Primary Completion Date: August 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
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

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

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.
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Please refer to this study by its identifier: 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
  More Information

Responsible Party: Johannes D. Veldhuis, M.D., Mayo Clinic Identifier: NCT00309855     History of Changes
Other Study ID Numbers: 319-03
Study First Received: March 31, 2006
Last Updated: July 27, 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 processed this record on August 22, 2017