Endothelin-1 secretion from cultured rabbit gastric epithelial cells.
It has been shown that endothelin-1 (ET-1) is synthesized in various extraendothelial tissues. Although ET-1 has been reported to have potent ulcerogenic action in the stomach, the synthesis and physiological roles of ET-1 in the gastric mucosa are poorly understood. The aim of the present study was to investigate whether or not cultured gastric epithelial cells secrete ET-1 and possess autocrine functions. Gastric epithelial cells from rabbits were cultured in medium supplemented with 10% FBS after isolation. ET-1 was extracted by C18 columns from serum-free culture media and measured by radioimmunoassay (RIA). Effects of ET-1 on the intracellular concentration of calcium of the cultured cells were examined with Indo-1. Prostaglandin E2 (PGE2) was measured by RIA. Primary cultures of gastric epithelial cells were mainly composed of mucous cells. ET-1 was detected in the culture medium by RIA, and 70 pg/10(6) cells/24 h of ET-1 was secreted by cultured cells. Tumor growth factor-beta (4 ng/ml) and thrombin (8 U/ml) significantly increased ET-1 secretion. Exogenously administered ET-1 up to 10(-6) M neither modulated the intracellular calcium concentration nor affected PGE2 release by these cells. These results suggest that gastric mucous cells in culture secrete ET-1. Further studies are needed to explore the possible involvement of such paracrine function in the reported ulcerogenic action of ET-1.
Ota
S
S
Second Department of Internal Medicine, University of Tokyo, Japan.
Hirata
Y
Y
Sugimoto
T
T
Kohmoto
O
O
Hata
Y
Y
Yoshiura
K
K
Nakada
R
R
Terano
A
A
Sugimoto
T
T
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism; D016232:Endothelins / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism*; D011817:Rabbits
D016232:Endothelins; D015232:Dinoprostone; D002118:Calcium