Pituicyte

Pituicytes are the principal cell type intrinsic to the posterior pituitary gland, making up 25-30% of the volume of the gland. They express glial fibrillary acidic protein, which identifies them as a subpopulation of astrocytic glial cells. Like other astrocytes, they are extensively interconnected by prominent gap junctions, via which they are electrotonically coupled. The cytoplasm contains abundant Golgi bodies, free ribosomes and lipid bodies. The pituicytes have long processes that extend among the neurosecretory axons that innervate the lobe and onto the basement lamina of the perivascular space. The morphology of the pituicytes changes dramatically in different physiological states.