So our LH stimulates the Thicka cells to produce androgens and the androgens are taken up by the other cells called the granulosis cells, also found the follicle and the granulosis cells, they use the androgens to produce estrogen. And that's exactly why, if we look at the diagram, when the follicle begins to develop, the estrogen concentration shown in green begins to increase in concentration. So we have an increase as shown here. Now, as estrogen increases, that causes the initiation of the thickening of the endometrium. And so as estrogen increases, the endometrium begins to thicken as a result. So the developing follicle begins to release estrogen, which stimulates the thickening and formation of the endometrium in preparation for the implantation.