Which hormone is NOT listed as involved in the menstrual cycle hormones?

• A. Adrenaline
• B. Gonadotropin-releasing hormone
• C. Estrogen
• D. Prostaglandins

Answer: (A)

The key idea is recognizing which hormones actively regulate the menstrual cycle. The cycle is driven by a hormonal cascade: GnRH from the hypothalamus stimulates the pituitary to release FSH and LH; FSH promotes ovarian follicle growth, and the follicles produce estrogen; rising estrogen leads to the proliferative phase of the endometrium and, near mid-cycle, triggers the LH surge that causes ovulation; after ovulation, the corpus luteum makes progesterone to maintain the secretory endometrium. Prostaglandins in the uterus help coordinate ovulation and menstrual shedding by affecting contractions and cervical changes. Adrenaline, on the other hand, is a stress-related hormone from the adrenal glands and is not part of the standard regulatory hormones of the menstrual cycle, though stress can influence cycle timing indirectly. So adrenaline is not listed as a menstrual cycle hormone, whereas GnRH, estrogen, and prostaglandins are.