Theca interna cells and granulosa cells work synergistically to produce the ovarian hormones within the follicle. Which of the following adverse physiological responses is the most likely outcome if a woman is treated with an LH receptor antagonist during the early proliferative phase of the menstrual cycle?
A. Estradiol levels will decline B. Progesterone levels will increase C. Androstenedione levels will increase D. LH levels will decline E. The follicle will undergo atresia and die
This question pertains directly to the 2cell theory of steroidogenesis. Theca
interna cells express LH receptors and, in response to LH, primarily produce androgens. These androgens then cross the
basement membrane and enter the granulosa cells, where these androgens are then converted (by the aromatase
enzyme) into estrogen (predominantly estradiol). By blocking the LH receptor, this pathway will be inhibited and
estradiol levels will decline. It is possible that the follicle will undergo atresia and die, but many follicles persist on low
levels of FSH and LH, which is why the proliferative phase can exhibit such extended variations in length.