Scientists at the National Institutes of Health have solved a long-standing mystery about the origin of one of the cell types that make up the ovary. The team also discovered how ovarian cells share information during development of an ovarian follicle, which holds the maturing egg. Researchers believe this new information on basic ovarian biology will help them better understand the cause of ovarian disorders, such as premature ovarian failure and polycystic ovarian syndrome, conditions that both result in hormone imbalances and infertility in women.
The ovarian follicle contains the egg surrounded by two distinct cell types, known as granulosa cells and theca cells. Scientists had known the cellular origins of the egg and granulosa cells, but did not know where theca cells came from or what directed their development. Without theca cells, women are unable to produce the hormones that sustain follicle growth.
One of the major hormones theca cells produce is androgen, which is widely thought of as a male hormone. The granulosa cells convert the androgen to estrogen. The researchers uncovered the molecular signaling system that enables theca cells to make androgen. This communication pathway is derived from granulosa cells and another structure in the ovary called the oocyte, or immature egg cell. The crosstalk among the egg, granulosa cells and theca cells was an unexpected finding, but one that may provide insight into how ovarian disorders arise.
More research needs to be done, and it may potentially uncover several roles theca cells play in female fertility, the researchers say.