Altrenogest is used in mares to synchronize scheduled breeding activity. In the suppression of estrous behavior in mares, this is usually related to mares that are used as performance horses.
It is derived from the human hormone progesterone. It prevents fertilization and increases the rate of transport of eggs from the fallopian tubes to the uterus in female ferrets when administered prior to ovulation.
Norethindrone is a progestin (a synthetic substance with properties similar to progesterone) that is best known as the first female oral contraceptive, or the “pill.”
17-Εstradiol and its selective receptor, ER-X, are not part of a classical hormone/receptor endocrine system but of a system with important autocrine/paracrine functions in the developing and adult brain.
