Insulin-like growth factor-I stimulates endothelin-3 secretion from rat anterior pituitary cells in primary culture.
Since we found relatively high concentrations of immunoreactive (ir-) ET-3 in the rat pituitary gland (190 pg/g tissue), we have investigated the possible ET-3 secretion from the primary culture of anterior pituitary cells and the effects of various growth factors on the ET-3 secretion. The ir-ET-3 was detected in the incubation medium within 2 h, and 24 h of culture attained the concentrations of 1.15 +/- 0.26 pg/well/6 x 10(5) cells. The ir-ET-3 secretion was stimulated by insulin, insulin like growth factor-II (IGF-II), and most effectively by insulin like growth factor-I (IGF-I) in a dose- and time-dependent manner, whereas the production of ir-ET-1 and ir-big ET-1 was slightly inhibited by IGF-I and IGF-II. In reverse-phase HPLC, the ir-ET-3 released into the culture media showed identical retention time with authentic ET-3. Although ir-ET-1 and ir-big ET-1 secretion was stimulated by transforming growth factor-beta (TGF-beta), ir-ET-3 secretion was inhibited. These results indicate that the anterior pituitary cells secrete ET-3 and the secretion is stimulated by IGF-I.
Matsumoto
H
H
Tsukuba Research Laboratories, Takeda Chemical Industries, Ltd., Ibaraki, Japan.
Suzuki
N
N
Shiota
K
K
Inoue
K
K
Tsuda
M
M
Fujino
M
M
D000818:Animals; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D016232:Endothelins / Q000302:isolation & purification / Q000378:metabolism*; D006133:Growth Substances / Q000494:pharmacology; D007124:Immunoenzyme Techniques; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D016232:Endothelins; D006133:Growth Substances; D007334:Insulin-Like Growth Factor I