Inclusion Criteria:

1. Late pubertal girls (Tanner breast stage 3, 4, or 5)

2. Postmenarcheal, but no more than 4 y postmenarcheal

3. Age 10-17 y

Exclusion Criteria:

1. Age < 10 or > 17 y

2. BMI-for-age < 5th percentile

3. Inability to comprehend what will be done during the study or why it will be done

4. Being a study of GnRH pulse regulation in adolescent girls with and without HA, boys
are excluded

5. Obesity associated with a diagnosed (genetic) syndrome (e.g., Prader-Willi syndrome,
leptin deficiency), obesity related to medications (e.g., glucocorticoids), etc.

6. Pregnancy or lactation

7. Virilization

8. Total testosterone > 150 ng/dl

9. DHEAS > upper limit of age-appropriate normal range (mild elevations may be seen in
adolescent HA, and elevations < 1.5 times the age-appropriate upper limit of normal
will be accepted in such girls)

10. 17-hydroxyprogesterone > 250 ng/dl, which suggests the possibility of congenital
adrenal hyperplasia (if postmenarcheal, the 17-hydroxyprogesterone will be collected
during the follicular phase, or >60 if oligomenorrheic). NOTE: If a
17-hydroxyprogesterone > 250 ng/dl is confirmed on repeat testing, an ACTH stimulated
17-hydroxyprogesterone < 1000 ng/dl will be required for study participation

11. History of premature adrenarche (i.e., appearance of pubic and/or axillary hair
before age 8)

12. A previous diagnosis of diabetes

13. Fasting glucose ≥ 126 mg/dl, or a hemoglobin A1c > 6.5% (confirmed on repeat)

14. Abnormal TSH (confirmed on repeat) (subjects with adequately treated hypothyroidism,
reflected by normal TSH values, will not be excluded)

15. Abnormal prolactin (confirmed on repeat) (mild elevations may be seen in HA girls,
and elevations < 1.5 times the upper limit of normal will be accepted in this group)

16. Evidence of Cushing's syndrome by history or physical exam (e.g., history of impaired
growth in children, striae)

17. Hematocrit < 36% and hemoglobin < 12 g/dl (specifically, documentation of a
hematocrit >= 36% or a hemoglobin >= 12 g/dl in the month prior to GCRC admission is
required for the frequent sampling protocol in the GCRC)

18. Significant history of cardiac or pulmonary dysfunction (e.g., known or suspected
congestive heart failure; asthma requiring intermittent systemic corticosteroids;
etc.)

19. Persistent liver test abnormalities (confirmed on repeat), with the exception that
mild bilirubin elevations will be accepted in the setting of known Gilbert's syndrome

20. Persistently abnormal sodium, potassium, or elevated creatinine concentration
(confirmed on repeat)

21. Bicarbonate concentrations < 20 or > 30 (confirmed on repeat)

22. No medications known to affect the reproductive system, glucose metabolism, lipid
metabolism, or blood pressure can be taken in the 3 months prior to the first
inpatient GCRC study (or in the 2 months prior to screening). Such medications
include oral contraceptive pills, progestins, metformin, glucocorticoids,
psychotropics, and sympathomimetics/stimulants (e.g., methylphenidate). Patients
taking restricted medications will be excluded unless written permission (for the
subjects to discontinue the medication) is received from the subject's physician.

23. Weight < 22 kg is an absolute exclusion criterion (to ensure safe blood withdrawal)

24. Personal history of deep venous thrombosis (DVT)

25. Personal history of ovarian, endometrial, or breast neoplasia