Pituitary adenylate cyclase-activating polypeptide induces somatolactin release from cultured goldfish pituitary cells.
In the goldfish pituitary, nerve fibers containing pituitary adenylate cyclase-activating polypeptide (PACAP) are located in close proximity to somatolactin (SL)-producing cells, and PACAP enhances SL release from cultured pituitary cells. However, there is little information about the mechanism of PACAP-induced SL release. In order to elucidate this issue, we used the cell immunoblot method. Treatment with PACAP at 10(-8) and 10(-7)M, but not with vasoactive intestinal polypeptide (VIP) at the same concentrations, increased the immunoblot area for SL-like immunoreactivity from dispersed pituitary cells, and PACAP-induced SL release was blocked by treatment with the PACAP selective receptor (PAC(1)R) antagonist, PACAP(6-38), at 10(-6)M, but not with the PACAP/VIP receptor antagonist, VIP(6-28). PACAP-induced SL release was also attenuated by treatment with the calmodulin inhibitor, calmidazolium at 10(-6)M. This led us to explore the signal transduction mechanism up to SL release, and we examined whether PACAP-induced SL release is mediated by the adenylate cyclase (AC)/cAMP/protein kinase A (PKA)- or the phospholipase C (PLC)/inositol 1,4,5-trisphosphate (IP(3))/protein kinase C (PKC)-signaling pathway. PACAP-induced SL release was attenuated by treatment with the AC inhibitor, MDL-12330A, at 10(-5)M or with the PKA inhibitor, H-89, at 10(-5)M. PACAP-induced SL release was suppressed by treatment with the PLC inhibitor, U-73122, at 3 x 10(-6)M or with the PKC inhibitor, GF109203X, at 10(-6)M. These results suggest that PACAP can potentially function as a hypophysiotropic factor mediating SL release via the PAC(1)R and subsequently through perhaps the AC/cAMP/PKA- and the PLC/IP(3)/PKC-signaling pathways in goldfish pituitary cells.
Azuma
Morio
M
Laboratory of Regulatory Biology, Graduate School of Science and Engineering, University of Toyama, 3190-Gofuku, Toyama 930-8555, Japan.
Tanaka
Mio
M
Nejigaki
Yumika
Y
Uchiyama
Minoru
M
Takahashi
Akiyoshi
A
Shioda
Seiji
S
Matsuda
Kouhei
K
D000067956:Adenylyl Cyclase Inhibitors; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000378:metabolism; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004963:Estrenes / Q000494:pharmacology; D005260:Female; D029941:Fish Proteins / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D006054:Goldfish; D006133:Growth Substances / Q000494:pharmacology*; D007093:Imidazoles / Q000494:pharmacology; D007097:Imines / Q000494:pharmacology; D015151:Immunoblotting; D007211:Indoles / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D008297:Male; D008301:Maleimides / Q000494:pharmacology; D054801:Phosphoinositide Phospholipase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000494:pharmacology*; D010902:Pituitary Gland / Q000166:cytology* / Q000378:metabolism*; D010907:Pituitary Hormones / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011760:Pyrrolidinones / Q000494:pharmacology; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide / Q000037:antagonists & inhibitors; D015398:Signal Transduction / Q000187:drug effects; D013449:Sulfonamides / Q000494:pharmacology; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
D000067956:Adenylyl Cyclase Inhibitors; D002147:Calmodulin; D004791:Enzyme Inhibitors; D004963:Estrenes; D029941:Fish Proteins; D006023:Glycoproteins; D006133:Growth Substances; D007093:Imidazoles; D007097:Imines; D007211:Indoles; D047908:Intracellular Signaling Peptides and Proteins; D007546:Isoquinolines; D008301:Maleimides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D010907:Pituitary Hormones; D011760:Pyrrolidinones; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D013449:Sulfonamides; C015482:protein kinase modulator; C064448:somatolactin protein, fish; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D014660:Vasoactive Intestinal Peptide; C031938:calmidazolium; C014925:RMI 12330A; D011493:Protein Kinase C; D054801:Phosphoinositide Phospholipase C; D000262:Adenylyl Cyclases; C070515:bisindolylmaleimide I; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide