The body responds to insult or injury by engaging the immune system

The immune cells of the brain, microglia and mast cells, coordinate with astrocytes to contain insults and assist in brain repair, by releasing:

• Prostaglandins

• Cytokines

• Free radicals

• growth factors

During development of the male medial preoptic area (mPOA)- a region crucial for expression of male sex behavior, males rats have significantly more active microglia than females

• A masculinizing dose of estradiol at given to female rats at birth both increases the number and activation state to that of males.