Role of Endogenous Estrogen in Growth-Hormone Regulation in Postmenopausal Women
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Purpose
Participants are being asked to take part in this research study to learn why growth hormone(GH) levels decline when estrogen production falls at the time of menopause. GH is a hormone released from the pituitary gland that affects bone, muscle, and fat. Estrogen is a female hormone. Doctors believe that lower estrogen is one of the reasons that GH diminishes in postmenopausal women. However, estrogen does not fall completely. This raises the question whether the little bit of estrogen that is left is doing anything. Lack of GH makes bones thinner, muscles weaker, and fat stores larger. To learn whether the low amount of the body's own estrogen maintains GH secretion after menopause, the investigators need to stop any estrogen you might be taking and then partially block the effect, if any, of your own estrogen. The investigators will use a new estrogen-blocking drug (fulvestrant). Fulvestrant(which also goes by the tradename, Faslodex) was recently approved by the Food and Drug Administration (FDA) to treat breast cancer. Fulvestrant is being used in a non-FDA approved manner in this study (not to treat breast cancer, but to study the effect on Growth Hormone secretion). The drug interferes with how estrogen works in the body, except in the brain. The study that you are considering now tests whether your own estrogen works outside the brain to maintain GH secretion in postmenopausal women. This concept is important, because the brain controls how the pituitary gland secretes GH.
| Condition | Intervention |
|---|---|
|
Healthy |
Drug: Fulvestrant |
| Study Type: | Interventional |
| Study Design: | Allocation: Randomized Endpoint Classification: Safety/Efficacy Study Intervention Model: Parallel Assignment Masking: Single Blind (Subject) Primary Purpose: Basic Science |
| Official Title: | Role of Endogenous Estrogen in Growth-Hormone Regulation in Postmenopausal Women |
- BioStatistical Analysis [ Time Frame: Withdrawal of blood samples (2.5 mL each) every 10 min for 6 hr. Sampling will begin at 0800 h and conclude at 1400 h. ] [ Designated as safety issue: Yes ]GH concentrations decrease with age gradually in premenopausal women and rapidly in ovariprival individuals. A prime focus of our clinical studies is how estradiol availability governs GH secretion via combined central and peripheral regulation of neuropeptide signaling. The present investigation extends this theme by assessing whether endogenous estrogen maintains GH output and, if so, whether estrogen acts via CNS or systemic mechanisms in postmenopausal individuals.
- BioStatistical Analysis [ Time Frame: Withdrawal of blood samples (2.5 mL each) every 10 min for 6 hr. Sampling will begin at 0800 h and conclude at 1400 h. ] [ Designated as safety issue: Yes ]The present study will utilize a highly specific ER antagonist, fulvestrant, which inhibits ER-dependent pathways in peripheral tissues but not in the CNS. The study subjects are postmenopausal women, for whom fulvestrant was developed as a treatment for estrogen-responsive breast cancer. The premise is that fulvestrant will impede the effects of estradiol at systemic sites (e.g. liver, pituitary gland and fat cells), but not in drug-inaccessible CNS sites (e.g. hypothalamic nuclei), thereby unveiling which sites are important in regulating GH secretion.
| Estimated Enrollment: | 38 |
| Study Start Date: | June 2009 |
| Estimated Study Completion Date: | December 2013 |
| Estimated Primary Completion Date: | June 2013 (Final data collection date for primary outcome measure) |
| Arms | Assigned Interventions |
|---|---|
| Experimental: Fulvestrant |
Drug: Fulvestrant
Secretagogue combinations are assigned in randomized double-blind order within-subject to include the following four conditions: (i)L-arginine (30 gm i.v. over 30 min from 0930 h to 1000 h) followed by 5 mL bolus of NS at 1000 h; (ii) L-arginine (30 gm i.v. over 30 min from 0930 h to 1000 h) followed by GHRH and Ghrelin (both at dose of 0.3 mcg/kg bolus i.v.) at 1000 h; (iii) L-arginine (30 gm i.v. over 30 min from 0930 h to 1000 h) followed by GHRH (0.3 μg/kg bolus i.v.) at 1000 h; (iv) L-arginine infusion (30 gm i.v. over 30 min from 0930 h to 1000 h) followed by Ghrelin (0.3 μg/kg bolus i.v.) at 1000 h. **Ghrelin dosage is based on 70 kg subject.Total exposure of Ghrelin will be 42 mcg total dose for 2 subject visits (21 mcg per visit). |
Detailed Description:
Hypotheses: Endogenous estrogen concentrations contribute significantly to maintaining postmenopausal growth-hormone (GH) secretion and; (b) systemic vis-à-vis CNS actions of endogenous estrogen differentially control the outflow of somatotropic hormones (viz., GH, IGF-I, IGFBP-1).
Approach: contrast regulation of the GH axis in postmenopausal women pretreated with the CNS-excluded selective estrogen-receptor antagonist, fulvestrant, versus placebo.
Background: fulvestrant was released recently by the FDA for therapy of estrogen-sensitive postmenopausal breast cancer. The drug acts as a mechanistically novel inhibitor of estradiol-receptor dimerization, thereby depleting nuclear estrogen receptors. Fulvestrant does not gain access to the CNS. Thus, inhibition of estrogen action will be restricted to non hypothalamic sites of GH-axis control, such as the pituitary gland, liver and fat cells. In contrast, endogenous estrogens have access to both CNS and peripheral sites.
Premise: selective blockade of peripheral estradiol receptors will reduce GH secretion if endogenous estrogens maintain GH secretion via systemic effects.
Eligibility| Ages Eligible for Study: | 50 Years to 80 Years |
| Genders Eligible for Study: | Female |
| Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
- healthy postmenopausal women (ages 50 to 80 y), wherein menopause is defined by the absence of spontaneous menses for 1 y and a serum concentration of FSH > 30 IU/L and of (ultrasensitive) estradiol < 20 pg/mL and verified by medical history and screening blood work;
- normal hemoglobin of >11.0 g/dL in women (a ferritin level will be drawn, and must be normal, if Hgb is 11.0 - 11.5) , Platelets greater than 200 x 109/L, AST 8-48 U/L.
- Subjects (age 50 and above) will have a screening baseline ECG if not on record from the past year.
Exclusion Criteria:
- exposure to psychotropic or neuroactive drug within five biological half- lives;
- undesirability, disinclination or ill advisability of withholding estrogen supplements (e.g. under treatment for symptomatic hot flushes; primary physician recommendation);
- BMI < 19 or > 35
- drug or alcohol abuse; psychosis, depression, mania or anorexia nervosa;
- acute or chronic organ or systemic inflammatory disease;
- endocrinopathy, other than primary thyroidal failure receiving replacement;
- although fulvestrant has no known intrinsic estrogenicity, for safety reasons we include contraindication to short-term estrogen exposure; e.g.,estrogen-sensitive neoplasia, undiagnosed vaginal bleeding, deep-venous thrombosis, stroke or threatened stroke, clinical evidence of atherosclerotic heart disease, including myocardial infarction and/or angina, refractory high blood pressure, severe type IV hyperlipidemia:
- nightshift work or recent transmeridian travel (exceeding 3 time zones within 5 days of admission);
- systemic anticoagulation other than anti platelet therapy (in view of i.m. injections of fulvestrant); history of bleeding diathesis (ie; disseminated coagulation (DIC), clotting factor deficiency
- acute weight change (> 3 kg in 6 weeks); and/or
- unwillingness to provide written informed consent.
- Platelets less than 200 x 109 /L
- International normalization ratio(INR) (Prothrombin time) greater than 1.6
- Total bilirubin greater than 1.5 x ULRR
- ALT or AST greater than 2.5 xULRR if no demonstrable liver metastases or greater
- History or hypersensitivity to active or inactive excipients of fulvestrant (ie; castor oil or Mannitol).
Contacts and Locations| Contact: Sue Weist, RN | 507-255-1294 | weist.suanne@mayo.edu |
| Contact: Jean Wigham, RN | 507-293-1188 | wigham.jean@mayo.edu |
| United States, Minnesota | |
| Mayo Clinic | Recruiting |
| Rochester, Minnesota, United States, 55905 | |
| Contact: Sue Weist, RN 507-255-1294 weist.suanne@mayo.edu | |
| Contact: Jean Wigham, RN 507-293-1188 wigham.jean@mayo.edu | |
| Principal Investigator: | Johannes Veldhuis, M.D. | Mayo Clinic |
More Information
No publications provided
| Responsible Party: | Johannes D. Veldhuis, Johannes D. Veldhuis, MD, Mayo Clinic |
| ClinicalTrials.gov Identifier: | NCT01186796 History of Changes |
| Other Study ID Numbers: | 07-003036 |
| Study First Received: | August 16, 2010 |
| Last Updated: | November 6, 2012 |
| Health Authority: | United States: Food and Drug Administration |
Keywords provided by Mayo Clinic:
|
Women Fulvestrant Study Post Menopausal Women Hormones Healthy Adult Women |
Additional relevant MeSH terms:
|
Estrogens Hormones Fulvestrant Hormones, Hormone Substitutes, and Hormone Antagonists Physiological Effects of Drugs Pharmacologic Actions |
Antineoplastic Agents Therapeutic Uses Estrogen Antagonists Estrogen Receptor Modulators Hormone Antagonists Antineoplastic Agents, Hormonal |
ClinicalTrials.gov processed this record on May 16, 2013