The pharmaceutical drug RU-486, typically used to treat Cushing's disease, is also sometimes used for medical abortions. RU-486 blocks progesterone production and its binding to receptors in the reproductive tract. Why would this affect pregnancy and embryonic growth?
A. Progesterone stops the corpus luteum from degrading. Without the corpus luteum, hCG (responsible for uterine growth and development) cannot be produced.
B. Progesterone maintains the endometrium and prevents it from breaking down and shedding in a normal menstrual period. It also assists in stopping uterine contractions until birth.
C. Progesterone stimulates release of aldosterone from the adrenal cortex. Without aldosterone, fluid is lost through the kidneys and causes high blood pressure in the uterus, which is fatal to the fetus.
D. Progesterone stimulates the ovaries to produce LH, which then causes hCG production. Production of hCG is needed to inhibit pituitary FSH secretion, which induces menstrual periods.
Answer: B
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