Progesterone

By Amelia Sisson

What is it?

· Progesterone is a hormone that signals the body to prepare the uterus with a lining of tissue in preparation for a fertilized egg

· If the egg does not get fertilized the level of the hormone will drop, this signals the body to shed the lining and menstruation to occur.

· In other words it helps prepare your body for conception and pregnancy and regulates the monthly menstrual cycle.

How does it work?

· The ovaries release progesterone around 2 weeks after a woman begins her menstrual cycle.

· Its function is to trigger the release of proteins that are essential for the endometrium, or lining of the uterus, to handle pregnancy.

· The proteins that are released make it possible for the endometrium (lining go the uterus) to hold onto a fertilized egg if necessary.

Where is it produced/stored?

Target cells and what is the reaction


  • Progesterone has many target cells but an example could be the cells in the uterus.
  • The hormone can diffuse freely through the plasma membrane of target cells
  • From there the hormone will bind with the progesterone receptor.
  • The receptor and its hormone move into the nucleus.
  • In the nucleus it binds to a progesterone response element
  • The progesterone response element is a specific sequence of DNA in the promotors of certain genes that is needed to turn those genes on or off.
  • Then the progesterone with its receptor forms a transcription factor.