Where is progesterone primarily released from?

Progesterone is primarily released from the corpus luteum and the placenta. The corpus luteum is a temporary endocrine structure that forms in the ovary after ovulation, playing a crucial role in regulating the menstrual cycle and maintaining early stages of pregnancy by producing progesterone. This hormone is vital for preparing the uterine lining for potential implantation of an embryo and for maintaining pregnancy if fertilization occurs.

During pregnancy, the placenta takes over the production of progesterone to support the pregnancy and sustain the developing fetus. This shift ensures that the embryo can continue to grow safe from rejection by the maternal immune system and that the necessary physiological changes occur in the mother’s body to support the pregnancy.

The other options do not primarily release progesterone: the testes predominantly produce testosterone, the adrenal glands primarily secrete hormones such as cortisol and adrenaline, and the pituitary gland regulates various hormone functions but does not release progesterone directly. Therefore, recognizing the roles of the corpus luteum and placenta in progesterone production is essential in understanding reproductive physiology.