Prior to Ovulation, the Primary Steroid Hormone Secreted by the Growing

Question

Prior to ovulation, the primary steroid hormone secreted by the growing follicle is
A) LH.
B) FSH.
C) inhibin.
D) GnRH.
E) estradiol.

Accepted Answer

The primary steroid hormone secreted by the growing follicle prior to ovulation is estradiol. Initially, FSH stimulates the growth of the follicles in the ovary, and one follicle becomes dominant. The dominant follicle secretes increasing amounts of estradiol, which stimulate the endometrium (lining of the uterus) to thicken and prepare for a potential embryo. As the estradiol levels rise, they cause an increase in LH secretion from the pituitary gland, which then triggers ovulation.