NCT01862835

Impact of Estradiol Addback

Impact of Estradiol Addback on Somatostatin Rebound in Older Men

• Status: Completed
• Phase: Phase 1
• Study type: Interventional
• Enrollment: 43 (actual)
• Sponsor: Mayo Clinic · Academic / Other
• Sex: Male
• Age: 60 Years – 80 Years
• Healthy volunteers: Accepted

Summary

Repletion of testosterone (T) in older men drives Growth Hormone secretion after its aromatization to estradiol (E2) by potentiating endogenous GH drive.

Detailed description

Systemic concentrations of Te, E2, GH, Insulin-like Growth Factor-I and IGFBP-3 decline in healthy aging men. Relative sex-steroid deprivation accentuates GH and IGF-I depletion, since Te stimulates GH and IGF-I production in older men, hypogonadal males of all ages, and patients undergoing (genotypic female-to-male) gender reassignment. Tamoxifen blocks this effect of Te, suggesting involvement of E2 in GH's stimulation in men. E2 per se stimulates GH secretion in women. Because Te is converted to E2 by aromatization in the body, we postulate that E2 is the active moiety in men also. Moreover, we hypothesize that the decline of E2 in older men contributes to the fall in GH output. This has never been tested. From a clinical vantage, understanding the mechanistic basis of Te's drive of the somatotropic axis is especially relevant in boys with pubertal failure, adults with primary hypogonadism and men with aging-related hypoandrogenemia. In relation to aging in the male, testosterone and E2 bioavailabilities fall by 35-50% in the eighth compared with third decade of life. From a medical perspective, aging is accompanied by progressive osteopenia, sarcopenia and intra-abdominal obesity. These adverse outcomes are remediable by short-term replacement with Te and/or recombinant GH, thus linking GH/Te/E2 availability with key body-compositional features.

Conditions

• Normal Healthy Volunteers

Interventions

Type	Name	Description
DRUG	Degarelix
DRUG	Testosterone
DRUG	Anastrozole
DRUG	Estrogen patch

Timeline

• Start date: 2013-05-01
• Primary completion: 2016-09-30
• Completion: 2018-12-30
• First posted: 2013-05-27
• Last updated: 2019-06-07

Locations

1 site across 1 country: United States