During the luteal phase of the menstrual cycle, which hormone is primarily responsible for maintaining the endometrium in the secretory phase?

• A Estradiol from theca cells
• B FSH from the anterior pituitary
• C hCG from the developing embryo
• D Progesterone from the corpus luteum ✓

Explanation

After ovulation, the granulosa cells of the ruptured follicle luteinize to form the corpus luteum, which secretes large amounts of progesterone (and some estradiol). Progesterone converts the estrogen-primed proliferative endometrium to the secretory phase, characterized by secretory gland development, glycogen storage, and increased vascularity — preparing for potential implantation. If fertilization does not occur, the corpus luteum regresses (luteolysis) over 14 days, progesterone falls, and menstruation ensues.

Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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