Study: NCT04671966

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Estradiol patch
Description: Brand name Climara for estrogen add back portion of study. Premenopausal women treated with a GnRH antagonist will be randomized to estrogen add-back or placebo. Thus, for women without contradictions to estrogen use, the risks associated with their use for the duration proposed in these studies (i.e., 6 days) are small. The respective estradiol regimen is a standard approved dose for treatment of hot flashes and the prevention of osteoporosis, and this dose will increase E2 to concentrations typically observed during the mid to late follicular phase of the menstrual cycle.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Cetrotide
Description: Premenopausal women will be treated with the gonadotropin-releasing hormone (GnRH) antagonist Cetrorelix for 6 days in order to suppress ovarian sex hormones. Cetrorelix may cause an anaphylactic reaction in volunteers with hypersensitivity to cetrorelix, GnRH or any other GnRH analogs, or extrinsic peptide hormones or mannitol. It may also cause hot flashes, headaches, and nausea. These are typically transient and of mild intensity. These effects are all reversible upon cessation of cetrorelix. Absence of pregnancy will be confirmed before drug administration.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Cetrotide
Description: Premenopausal women will be treated with the gonadotropin-releasing hormone (GnRH) antagonist Cetrorelix for 6 days in order to suppress ovarian sex hormones. Cetrorelix may cause an anaphylactic reaction in volunteers with hypersensitivity to cetrorelix, GnRH or any other GnRH analogs, or extrinsic peptide hormones or mannitol. It may also cause hot flashes, headaches, and nausea. These are typically transient and of mild intensity. These effects are all reversible upon cessation of cetrorelix. Absence of pregnancy will be confirmed before drug administration.

Intervention type: OTHER
Group type: EXPERIMENTAL
Intervention: Fasting
Description: Subjects will abstain from food for 48 hours. Subjects will be allowed water and/or an isotonic saline solution in order to maintain hydration status.

Intervention type: OTHER
Group type: EXPERIMENTAL
Intervention: Fasting
Description: Subjects will abstain from food for 48 hours. Subjects will be allowed water and/or an isotonic saline solution in order to maintain hydration status.

Intervention type: OTHER
Group type: EXPERIMENTAL
Intervention: Fasting
Description: Subjects will abstain from food for 48 hours. Subjects will be allowed water and/or an isotonic saline solution in order to maintain hydration status.

Intervention type: OTHER
Group type: EXPERIMENTAL
Intervention: Lower Body Negative Pressure
Description: This test simulates Earth's gravity. The subject will rest on his/her back, with their lower body sealed in an air-tight chamber from the waist down. The chamber is connected to a vacuum that sucks air from the chamber and creates negative pressure inside and around the subject's lower body. As a result, the subject's blood pool shifts towards their legs, away from their chest and arms.