• A. Healthy Subjects

• All healthy subjects will meet the following criteria:

• normal puberty with respect to onset and pace,

• no chronic diseases,

• no difficulty with blood draws,

• no prescription medications for at least 2 months with the exception of seasonal allergy medications and hormone replacement therapy,

• no illicit drug use or excessive alcohol consumption (\< 10 drinks/week),

• no history of a medication reaction requiring emergency medical care,

• normal physical exam and laboratory studies within protocol reference ranges.

• Additional criteria based on subject population:

⁃ Healthy Men:

∙ between 21 and 40 years old,

‣ normal erectile and ejaculatory function, no history of reproductive disorders,

‣ testicular volume \>15 ml.

⁃ Healthy women:

∙ between 21 and 40 years old,

‣ not breastfeeding or pregnant,

‣ menstrual cycles between 25 and 35 days in duration, at least 11 periods/year, with no more than 5 days variability in cycle duration,

‣ no evidence for androgen excess (hirsutism or acne),

‣ at screening, negative hCG pregnancy test,

‣ negative screening for Factor V Leiden for those who might receive estradiol treatment as a part of this study.

⁃ Healthy postmenopausal women:

∙ between 50 and 60 years old,

‣ no menstrual periods within the last year,

‣ previous history of menstrual cycles between 25 and 35 days in duration, with no more than 5 days variability in cycle duration,

‣ if applicable, able to undergo washout from hormone therapy,

‣ no evidence for androgen excess (hirsutism or acne),

‣ negative screening for Factor V Leiden for those who might receive estradiol treatment as a part of this study.

• B. Subjects with Reproductive Disorders

• All subjects with reproductive disorders will meet the following criteria:

• 18 years or older,

• all medical conditions stable and well controlled,

• no prescription medications known to affect reproductive endocrine function for at least 2 months except for medications used to treat the subject's reproductive condition,

• no history of a medication reaction requiring emergency medical care,

• no illicit drug use or excessive alcohol consumption (\<10 drinks/week),

• for women, not breastfeeding or pregnant,

• if applicable, able to undergo appropriate washout from hormone therapy,

• normal physical exam and laboratory studies within protocol reference ranges,

• for women, at time of screening negative hCG pregnancy test.

• Additional criteria based on subject population:

⁃ Men and women with hypogonadotropic hypogonadism,

∙ Confirmed diagnosis by low sex steroids in the setting of low or inappropriately normal gonadotropins,

‣ If needed, additional labs and imaging tests may be performed.

⁃ Women with Polycystic Ovarian Syndrome (PCOS)

∙ Confirmed diagnosis of PCOS,

‣ If needed, additional labs and imaging tests may be performed.

⁃ Men and women with hyperprolactinemia

∙ confirmed diagnosis of elevated levels of prolactin measured via blood test,

‣ no pituitary adenoma OR a microprolactinoma (\<10 mm). Patients with a macroprolactinoma confirmed on MRI imaging will be excluded,

‣ willing to complete a dopamine agonist washout.