Figure 1.

Immunostaining for Tau-1 (A–C) and MAP-2 (D–F) of E16.5 neocortical neurons cultured for 4 days. DHEA 10⁻¹² M (B, E), DHEAS 10⁻¹² M (C and F), or vehicle (0.1% dimethyl sulfoxide) (A and D) were added to the cultures for the last 20 h. DHEA promotes the abundance of Tau-1⁺ neurites (B). Vehicle or DHEAS has no effect on Tau-1⁺ neurites. Very few cell bodies were immunostained with the anti-Tau-1 antibody and no MAP-2⁺ dendrites were double-stained with the anti-Tau-1 antibody, suggesting that in our cultures, the cellular localization of Tau-1 is restricted to axons. However, the immunostaining with the anti-MAP-2 antibody was cytoplasmic and extended into dendrites. DHEA and DHEAS (E and F) increased MAP-2 staining in the cell bodies, but only DHEAS increased MAP-2⁺ neurite length (F). There are many faintly MAP-2⁺ collaterals and clustering of the neurons when cells are cultured with DHEAS. (Bar = 100 μm).