Yes, the progeny of stem cells are the PROGENITOR CELLS, which are essential for producing hair. My guess is that prostaglandin balance in and around the follicle is key to switching the stem cells “on” so they become progenitor cells. I think the TACs described here are a type of progenitor cell which signals the DP cells to proliferate. Too much PGD2 probably turns the stem cells off and stops all progenitor cell production.
Here is another link not directly related hair loss but on the same road