title: Freeze-etch study of the teleostean pituitary.
abstract: The structure of membranes in the pituitary of several teleostean species was studied with the freeze-etching technique. Nuclear pore density is higher in hormone-secreting than in stellate cells, suggesting a higher rate of nucleo-cytoplasmic interactions in the secretory cells. The perinuclear endoplasmic reticulum (ER) in the MAS-secreting cells has a large number of fenestrae, whereas in the ER whorls of the prolactin-secreting cells the fenestration occurs only rarely. Three different types of membrane specializations are described, presumably related to exo-endocytotic events at the level of the plasmalemma.
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000648:ultrastructure; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D004705:Endocytosis; D004721:Endoplasmic Reticulum / Q000648:ultrastructure; D005089:Exocytosis; D005399:Fishes / Q000033:anatomy & histology*; D006056:Golgi Apparatus / Q000648:ultrastructure; D009685:Nuclear Envelope / Q000648:ultrastructure; D010902:Pituitary Gland / Q000648:ultrastructure*; D010903:Pituitary Gland, Anterior / Q000648:ultrastructure; D012487:Salmonidae / Q000033:anatomy & histology*; D014337:Trout / Q000033:anatomy & histology*