Astrocyte Growth Supplement-Animal (AGS-a) is a medium supplement designed for the optimal growth of normal animal (rat or mouse) astrocytes in vitro. It is a sterile, concentrated (100X) solution which contains growth factors, hormones, and proteins necessary for the culture of normal animal astrocytes. The supplement is formulated (quantitatively and qualitatively) to provide a defined and optimally balanced growth environment that maximally promotes the growth of normal animal astrocytes in vitro. The supplement is designed as an additive for astrocyte medium-animal (AM-a, Cat. No. 1831) and should be used in conjunction with that medium.