How insulin interferes with ovulation
The most iconic feature of PCOS and what the syndrome is named for — is the presence of the multiple cysts on the ovary. Many women have a few cysts on their ovary, but the sheer number of cysts distinguishes this syndrome from virtually all others. Almost no other human disease causes polycystic ovaries. These cysts develop from a group of cells known as follicles.
Normal ovaries are endowed at birth with a finite pool of primordial follicles, which have the potential to develop into a mature egg. Primordial follicles remain quiescent for many years until recruited for growth into a primary follicle during the menstrual cycle. From birth to menarche, all primordial follicles remain dormant. Follicle numbers gradually decrease with age as used follicles are never replaced. When the follicles are fully depleted, women undergo menopause and can no longer have children.
At the start of each menstrual cycle, a few primordial follicles grow into primary and then secondary follicles. Only one of these follicles is selected to become the dominant follicle and the rest simply shrivel away (involute) and are reabsorbed by the body. The dominant…
