Which hormone stimulates ovulation, the development of the corpus luteum, and the secretion of progesterone?

• A. Luteinizing hormone (LH)
• B. Adrenocorticotropic hormone (ACTH)
• C. Melanocyte-stimulating hormone (MSH)
• D. Thyroid-stimulating hormone (TSH)

Answer: (A)

Luteinizing hormone drives the key events of ovulation and the subsequent formation and function of the corpus luteum. A surge in this hormone triggers the release of the oocyte from the follicle. That same surge promotes luteinization, transforming the ruptured follicle into the corpus luteum, which then secretes progesterone to prepare and maintain the uterine lining for possible implantation. If pregnancy occurs, signals from the developing embryo (hCG) sustain the corpus luteum so progesterone continues to be produced. If there’s no pregnancy, the corpus luteum degenerates and progesterone falls, leading to the start of menstruation. The other hormones listed act on different glands and don’t control ovulation or progesterone production.