In which organ is progestin primarily produced?

Progestin, specifically progesterone, is primarily produced in the ovaries, particularly by the corpus luteum after ovulation. This hormone is crucial for regulating various aspects of the menstrual cycle and maintaining pregnancy. In the ovarian cycle, after an egg is released, the ruptured follicle transforms into the corpus luteum, which secretes progesterone. This hormone prepares the endometrium for potential implantation of a fertilized egg and maintains the uterine environment suitable for sustaining a pregnancy.

While the adrenal glands do produce certain steroid hormones, including some androgens and mineralocorticoids, the ovaries are the primary site for progestin synthesis in women. The testes are involved in testosterone production, and the pituitary gland primarily secretes hormones that regulate the functioning of other glands but does not produce progestin itself. Thus, the ovaries are the definitive source for progestin in the body.