Figure 3.

Electron micrograph of chromaffin cells of TH-null and WT mice at P15. In WT mice, chromaffin cells display cytoplasm filled with chromaffin vesicles, the darkly stained secretory granules (A). In TH-null mice adrenomedullary cells are depleted in chromaffin vesicles (CV) (B), Nuc, nucleus. (Bar = 0, 5 μm.) Frequently remaining chromaffin vesicles are lining up along the cell membrane (see arrows, C and D). The cells contain large amounts of rough endoplasmic reticulum (Rer) and oval-shaped or elongated mitochondria (Mit) (C and D) (Bar = 0, 1 μm.)