Injury-induced expression of glial androgen receptor in the zebra finch brain.

Astrogliosis occurs following injury to the zebra finch brain. To date, only estrogen synthase (aromatase) has been identified in injury-induced astrocytes. The expression of other steroidogenic enzymes or their receptors remains unknown in the avian brain. However, in mammals, an upregulation of androgen receptors has been identified in glial cells. The aim of this study was to determine if the androgen receptor is upregulated following injury in adult zebra finches. Finches were given a single penetrating injury and brain tissue was collected 24 or 72 h later. Expression of androgen receptor was examined using immunohistochemistry and quantified using quantitative polymerase chain reaction (qPCR) analysis. Androgen receptors were localized to astrocytes versus neurons, further solidifying the role for astrocytes in neural recovery.