title: Three-dimensional ultrastructural analyses of anterior pituitary gland expose spatial relationships between endocrine cell secretory granule localization and capillary distribution.
abstract: Endocrine and endothelial cells of the anterior pituitary gland frequently make close appositions or contacts, and the secretory granules of each endocrine cell tend to accumulate at the perivascular regions, which is generally considered to facilitate secretory functions of these cells. However, three-dimensional relationships between the localization pattern of secretory granules and blood vessels are not fully understood. To define and characterize these spatial relationships, we used scanning electron microscopy (SEM) three-dimensional reconstruction method based on focused ion-beam slicing and scanning electron microscopy (FIB/SEM). Full three-dimensional cellular architectures of the anterior pituitary tissue at ultrastructural resolution revealed that about 70% of endocrine cells were in apposition to the endothelial cells, while almost 30% of endocrine cells were entirely isolated from perivascular space in the tissue. Our three-dimensional analyses also visualized the distribution pattern of secretory granules in individual endocrine cells, showing an accumulation of secretory granules in regions in close apposition to the blood vessels in many cases. However, secretory granules in cells isolated from the perivascular region tended to distribute uniformly in the cytoplasm of these cells. These data suggest that the cellular interactions between the endocrine and endothelial cells promote an uneven cytoplasmic distribution of the secretory granules.
authors: Division of Microscopic and Developmental Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, 830-0011, Japan.|Department of Neurosurgery, Kurume University School of Medicine, 830-0011, Japan.
authors: Munetake
authors: M
authors: Yoshitomi
authors: Division of Microscopic and Developmental Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, 830-0011, Japan.|Electron Microscopic Research Unit, Central Research Unit of Kurume University, Kurume, 830-0011, Japan.
authors: Keisuke
authors: K
authors: Ohta
authors: Division of Microscopic and Developmental Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, 830-0011, Japan.
authors: Tomonoshin
authors: T
authors: Kanazawa
authors: Electron Microscopic Research Unit, Central Research Unit of Kurume University, Kurume, 830-0011, Japan.
authors: Akinobu
authors: A
authors: Togo
authors: Division of Microscopic and Developmental Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, 830-0011, Japan.
authors: Shingo
authors: S
authors: Hirashima
authors: Division of Microscopic and Developmental Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, 830-0011, Japan.
authors: Kei-Ichiro
authors: KI
authors: Uemura
authors: Division of Microscopic and Developmental Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, 830-0011, Japan.
authors: Satoko
authors: S
authors: Okayama
authors: Department of Neurosurgery, Kurume University School of Medicine, 830-0011, Japan.
authors: Motohiro
authors: M
authors: Morioka
authors: Division of Microscopic and Developmental Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, 830-0011, Japan.
authors: Kei-Ichiro
authors: KI
authors: Nakamura
mesh_terms: D000818:Animals; D003198:Computer Simulation; D003594:Cytoplasmic Granules / Q000378:metabolism*; D055098:Endocrine Cells / Q000145:classification / Q000473:pathology / Q000648:ultrastructure*; D042783:Endothelial Cells / Q000145:classification / Q000473:pathology / Q000648:ultrastructure*; D007150:Immunohistochemistry; D008297:Male; D008855:Microscopy, Electron, Scanning; D010903:Pituitary Gland, Anterior / Q000033:anatomy & histology / Q000648:ultrastructure*; D051381:Rats; D017208:Rats, Wistar