Immunohistochemical analysis of cholecystokinin A receptor distribution in the rat pancreas.
Cholecystokinin (CCK) plays a major role in the regulation of pancreatic enzyme secretion based on its binding to the CCK-A receptor (CCK-AR). While CCK-AR is known to be expressed in rat islet B cells, the localization of CCK-AR in rat pancreatic A and D cells remains poorly understood. The aim of this study was to identify the localization of CCK-AR in rat pancreatic islets by means of double immunofluorescence straining with antibodies against CCK-AR, glucagon, insulin and somatostatin and with in situ hybridization to detect its transcript. CCK-AR-like immunoreactive cells were found to overlap both with glucagon-like immunoreactive cells and insulin-like immunoreactive cells but not with somatostatin-like immunoreactive cells. An in situ hybridization study using a cRNA probe for CCK-AR revealed that CCK-AR mRNA was expressed in the center and periphery of the pancreatic islets. Further to this, immunofluorecsence staining using anti-glucagon antibody was carried out after in situ hybridization using the CCK-AR cRNA probe in order to identify CCK-AR mRNA expressing cells. CCK-AR mRNA exhibited a distribution pattern almost identical to that of glucagon-like immunoreactive cells. These results show clearly that CCK-AR exists not only in B but also in A cells of the rat pancreas, suggesting that CCK regulates the secretion of insulin and glucagon at least partly via CCK-AR.
Kageyama
Haruaki
H
Department of Anatomy, Showa University School of Medicine, 1-5-8 Hatanodai Shinagawa-ku, Tokyo 142-8555, Japan.
Kita
Tetsuro
T
Horie
Shigeru
S
Takenoya
Fumiko
F
Funahashi
Hisayuki
H
Kato
Sachi
S
Hirayama
Masami
M
Young Lee
Eun
E
Sakurai
Junko
J
Inoue
Shuji
S
Shioda
Seiji
S
D000818:Animals; D002766:Cholecystokinin / Q000378:metabolism; D005934:Glucagon / Q000378:metabolism; D007150:Immunohistochemistry; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000166:cytology / Q000502:physiology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D043886:Receptor, Cholecystokinin A / Q000096:biosynthesis*
D007328:Insulin; D043886:Receptor, Cholecystokinin A; D005934:Glucagon; D002766:Cholecystokinin