The Role of Kisspeptin in the Reproductive System

Eligibility Details: A. Healthy Subjects All healthy subjects will meet the following criteria: - normal puberty with respect to onset and pace, - no difficulty with blood draws, - no prescription medications for at least 2 months with the exception of asthma medication (albuterol only), hypercholesterolemia medication and psychiatric medication, - 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: 1. Healthy Men: - between 21 and 40 years old, - normal erectile and ejaculatory function, no history of reproductive disorders, - testicular volume >15 ml. 2. Healthy women: - between 21 and 40 years old, - not breastfeeding or pregnant, - menstrual cycles between 25 and 35 days in duration with no more than 5 days variability in cycle duration, - no evidence for androgen excess (hirsutism or acne), 3. Healthy postmenopausal women: - between 48 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: - all medical conditions stable and well controlled, medications allowed include asthma medication (albuterol only), hypercholesterolemia medication and psychiatric medication, - no 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, Additional criteria based on subject population: 1. Men and women with hypogonadotropic hypogonadism, - 18 years or older, - 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. 2. Agonadal men, - Between 18 and 60 years old.