Question

Refer to the given graph representing interplay of different hormones (A-D) during menstrual cycle in women and answer the questions that follow.
Which hormone (A, B, C or D) is necessary for the final follicular growth and ovulation?

• A. A
• B. B
• C. C
• D. D

Answer 1

The correct option is C C

C represents LH which is necessary for final follicular growth and ovulation. Without this hormone, even when large quantity of FSH is available, the follicle will not progress to the stage of ovulation. During the first 11 to 12 days of this follicle growth, the rates of pituitary secretion of the gonadotropins FSH and LH decrease slightly because of the negative feedback effect, mainly of estrogen, on the anterior pituitary gland. The high level of estrogens at this time (or the beginning of progesterone secretion by the follicles) causes a positive feedback stimulatory effect on the anterior pituitary, which leads to a surge in the secretion of LH and, to a lesser extent, FSH.

The rate of secretion of LH by the anterior pituitary gland increases markedly, rising 6 to 10 folds and peaking about 16 hours before ovulation. FSH also increases about 2-folds to 3-folds at the same time, and the FSH and LH as synergistically to cause rapid swelling of the follicles during the last few days before ovulation. Without the initial preovulatary surge of LH, ovulation will riot take place.

So, the correct answer is 'C'.