Researchers Identify Protein Essential For Embryo Implantation

Researchers Identify Protein Essential For Embryo Implantation: Researchers funded by the National Institutes of Health have identified a key step in the establishment of a pregnancy. Their discovery shows how the hormone progesterone suppresses the growth of the uterus’s lining so that a fertilized egg can implant in the uterus. This key step, the researchers discovered, occurs when a protein called Hand2 suppresses the chemical activity that stimulates growth of the uterine lining, also known as the uterine epithelium.

At the start of each menstrual cycle, levels of the hormone estrogen begin to rise. Estrogen stimulates the cells in the uterine lining to increase in number, causing the epithelium to thicken. However, as the ovary releases an egg, levels of the hormone progesterone begin to rise. The elevated progesterone levels put the brakes on the estrogen-driven growth of the uterine epithelium. In this study, the researchers discovered that Hand2, previously found to increase in uterine cells as progesterone levels rise, is the switch that turns off estrogen’s stimulating effect on the epithelium.