Most parenchymal Prss56 cells express GFAP. (a, c, d) Sections shown from two 15 week-old rats with high Prss56 expression in tanycytes; parenchymal Prss56 cells are in the boxed areas or indicated by arrowheads. Cells in boxed areas are shown in high magnification in insets, and in b. GFAP immunofluorescence is shown in red, nuclear DAPI signal in blue. Most, though not all, Prss56 cells also contain GFAP. In the high magnification images, white arrowheads indicate two (D) or multiple (M) closely adjacent Prss56 cells; open arrowheads point to tanycyte processes adjacent to Prss56 cells. 3v, third ventricle; Arc, arcuate nucleus; VMH, ventromedial nucleus. Scale bars: 200 μm on a (for a, c, d); 10μm on top left inset (also for b, and all insets except in d); 10μm on inset of d.