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

Mayo Clinic

Status and phase: Completed; Phase 1

Conditions: Aging

Treatments: Drug: Testosterone; Drug: Dutasteride; Drug: Anastrazole; Drug: Placebo

Study type: Interventional

Funder types: Other; Industry

Identifiers

NCT00309855

319-03

Details and patient eligibility

About

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.

Full 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

Enrollment: 80 patients

Sex: Male

Ages: 50 to 80 years old

Volunteers: Accepts Healthy Volunteers

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.

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Double Blind

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80 participants in 4 patient groups, including a placebo group

Double Placebo

Placebo Comparator group

Description:

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

Treatment:

Drug: Placebo

Testosterone IM and oral placebo

Other group

Description:

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

Treatment:

Drug: Testosterone

Testosterone and Oral Anastrozole

Other group

Description:

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

Treatment:

Drug: Anastrazole

Drug: Testosterone

Testosterone and Dutasteride

Other group

Description:

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

Treatment:

Drug: Testosterone

Drug: Dutasteride