Assessment of Sensitivity of the Hypothalamic GnRH Pulse Generator to Estradiol and Progesterone Inhibition

Not Applicable

Terminated

Brief Summary: Gonadotropin-releasing hormone (GnRH) is a hormone that regulates the ability of the pituitary to secrete two hormones, luteinizing hormone (LH) and follicle-stimulating hormone (FSH). LH and FSH control the production of female hormones (such as estrogen and progesterone) and the development of eggs by the ovary. Progesterone and estrogen then decrease the number of GnRH pulses produced by the brain (and therefore the number of LH pulses from the pituitary). The ability to decrease GnRH pulses seems to be very important for normal menstrual function in adult women. The purpose of this study is to learn more about how GnRH and LH pulses are controlled during puberty. The information gathered in this study will hopefully allow us to learn more about how menstrual cycles are normally established in girls during puberty.

Detailed Description: In this study, the investigators will aim to discover the effect of 7 days of estrogen and progesterone on GnRH pulses in girls in early and mid puberty. Ultimately, if the investigators understand these normal processes, the investigators may be able to better understand abnormalities of puberty.

Recruitment & Eligibility

Inclusion Criteria

Exclusion Criteria

Abnormal screening labs
Congenital adrenal hyperplasia
Hyperandrogenism (e.g., hirsutism, elevated free testosterone level)
Hemoglobin <12 mg/dL or hematocrit < 36% (Subjects will be offered the opportunity to take iron supplementation for 60 days if their hematocrit is slightly low (33-36%) (suggestive of iron deficiency anemia) and will then return for retesting of their hemoglobin/hematocrit.)
Weight < 31 kg
History of peanut allergy, deep venous thrombosis, breast cancer, endometrial cancer, or cervical cancer
On hormonal medications (including oral contraceptive pills) or on medications known to affect the reproductive axis within 3 months of the study
Pregnant or breast feeding
Participation in a research study within the past 30 days that involved taking a study drug.
Participation in a research study that involved taking up to or greater than 473 ml's of blood within the past 60 days.
Cigarette smoking
History of surgery that required bedrest within the past 30 days
Family history of hypercoagulability or unexplained thromboembolic disease (not in setting of bedrest, surgery, or malignancy)
In order to ensure an adequate number of younger girls, no more than 4 enrolled subjects will be Tanner stage 3

Arm && Interventions

Group	Intervention	Description
Progesterone, estrace	Estrace (estrogen)	oral progesterone suspension (20 mg/ml, 25-100 mg) three times a day at 0700, 1500, and 2300 hr to achieve mean plasma concentrations over the range of 2-8 ng/ml for seven days oral estrace, 0.5-1 mg once a day for seven days
Progesterone, estrace	Progesterone	oral progesterone suspension (20 mg/ml, 25-100 mg) three times a day at 0700, 1500, and 2300 hr to achieve mean plasma concentrations over the range of 2-8 ng/ml for seven days oral estrace, 0.5-1 mg once a day for seven days

Primary Outcome Measures

Name	Time	Method
LH Pulse Frequency as a Function of Day 7 Progesterone	7 days following oral estrace and progesterone administration	number of LH pulses per 11 hours on Day 7 of progesterone

Secondary Outcome Measures