Proliferating cells in the rat anterior pituitary during the postnatal period: immunoelectron microscopic observations using monoclonal anti-bromodeoxyuridine antibody.
Proliferating cells in the male rat anterior pituitary at 1, 3, 5, and 8 weeks of age were labeled with bromodeoxyuridine (BrdU) and studied by light and electron microscopic immunocytochemistry using anti-BrdU. They decreased in number from 402+/-31/mm(2) at 1 week to 50+/-1.5/mm(2) at 8 weeks, while their cell area increased by about twofold during this period. They had a slightly higher nucleus/whole cell (N/C) ratio than non-proliferating cells. According to their ultrastructure we classified them into granular and agranular cells. The percentage of granular cells ranged from 73% to 82% of all the proliferating cells during the period studied. They had many granules of various sizes and shapes, and some contained growth hormone and prolactin. Agranular cells, constituting 18-27% of proliferating cells, were small and had a high N/C ratio, indicating their immaturity. Moreover, they showed several features of folliculo-stellate (FS) cells: they showed no secretory granules in the cytoplasm, extended thin cytoplasmic processes, and sometimes they constructed a follicle among them. These results suggest: (1) the majority of proliferating cells were mature cells producing anterior pituitary hormone(s) and (2) most of the agranular proliferating cells maybe FS cells. The possibility of the latter is discussed.
Kominami
Rieko
R
Department of Anatomy, Kanazawa Medical University, Uchinada, 920-0293 Ishikawa, Japan. riekom@kanazawa-med.ac.jp
Yasutaka
Satoru
S
Taniguchi
Yutaka
Y
Shinohara
Harumichi
H
D000818:Animals; D000911:Antibodies, Monoclonal; D001973:Bromodeoxyuridine / Q000276:immunology; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism* / Q000648:ultrastructure; D048429:Cell Size; D013006:Growth Hormone / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D016253:Microscopy, Immunoelectron; D010903:Pituitary Gland, Anterior / Q000254:growth & development* / Q000648:ultrastructure; D011388:Prolactin / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D000911:Antibodies, Monoclonal; D011388:Prolactin; D013006:Growth Hormone; D001973:Bromodeoxyuridine