Effect of Race on Gonadotropin Responses

Summary

The purpose of this study is to attempt to determine why estrogen levels are increased in African-American women as compared to Caucasian women by evaluating estrogen feedback on the brain. African-American women have increased bone mineral density, higher rates of twins, greater incidence of fibroids, and increased incidence of breast cancer below 40 years of age as compared to Caucasian women. These traits or illnesses are all believed to be estrogen-dependent. In fact, previous research has demonstrated increased estrogen levels in African-American women as compared to Caucasian women. However, the reason for these differences in estrogen levels has not been studied in humans. One possibility is that estrogen feedback on the brain differs between African-American and Caucasian women. Two small glands in the brain (hypothalamus and pituitary) respond to estrogen. The hypothalamus secretes GnRH (Gonadotropin-Releasing Hormone) that signals the pituitary to secrete the reproductive hormones, LH (Luteinizing Hormone) and FSH (Follicle Stimulating Hormone). These hormones act on the ovaries and signal the ovaries to produce estrogen and progesterone. Estrogen in the bloodstream then acts on the brain to stop this system when the blood has enough estrogen levels. This is called estrogen feedback. This study will determine whether there are differences in estrogen feedback between African-American and Caucasian women.

Conditions

• Premenopause
• Healthy

Interventions

DRUG

Estradiol steroid infusion

Estradiol infusion of 0.1 mcg/kg/hr for 12 hr, 0.135 mcg/kg/hr for 12 hr, 0.165 mcg/kg/hr for 12 hr and 0.2 mcg/kg/hr for 60 hr

DRUG

Progesterone steroid infusion

Progesterone infusion of 4.77 nmol/kg/hr (1.5 mcg/kg/hr) for 24 hr and 6.36 nmol/kg/hr (2 mcg/kg/hr) for the final 24 hr

Sponsors & Collaborators

• National Institutes of Health (NIH)

  collaborator NIH

• National Institute on Aging (NIA)

  collaborator NIH

• Massachusetts General Hospital

  lead OTHER

Principal Investigators

• Janet E Hall, M.D. · Massachusetts General Hospital

Study Design

Allocation

NON_RANDOMIZED

Purpose

OTHER

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

35 Years

Sex

FEMALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2005-01-31

Primary Completion

2011-12-31

Completion

2011-12-31

FDA Drug

Yes

Countries

• United States

Study Locations