Effect of Race on Gonadotropin Responses

• Status: Completed
• Trial end date: 2011-12-01
• Target enrollment: 0
• Participant gender: Female

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.

• Phase: Phase 1/Phase 2
• Accepts Healthy Volunteers?: Accepts Healthy Volunteers

Details

• Lead Sponsor: Massachusetts General Hospital
• Collaborators: National Institute on Aging (NIA); National Institutes of Health (NIH)
• Treatments: Estradiol; Estradiol 17 beta-cypionate; Estradiol 3-benzoate; Estradiol valerate; Polyestradiol phosphate; Progesterone

Criteria

Inclusion Criteria:

• African-American women aged 18 to 35 years and Caucasian women aged 18 to 36 years. Subjects will be asked to volunteer information on ethnicity (self classification). Only African-American and Caucasian subjects will be included in this aim to address the specific hypotheses.

• BMI <30

• In good general health with normal TSH, prolactin and hemoglobin

• Normal BUN and Creatinine (< 2 times the upper limit of normal)

• On no medications for > 2 months before the study

• Regular menstrual cycles every 25 to 35 days and ovulation documented by a luteal phase progesterone > 3 ng/ml

• Willing to use abstinence or barrier methods of contraception for the duration of the study.

Exclusion criteria:

• postmenopausal

• smoking >9 cigarettes per day

• evidence of androgen excess.

• sensitivity to any medications used in the relevant protocol

• race other than African-American or Caucasian

• Hispanic ethnicity