Effect of PT-treatment on ANP-mediated inhibition of adenylate cyclase and amylase release in rat parotid gland.
Effects of pertussis toxin (PT) treatment on atrial natriuretic peptide (ANP)-mediated inhibition of adenylate cyclase and amylase release were investigated in rat parotid gland. Adenylate cyclase activity stimulated by GTP gamma S in PT-treated membranes was much larger than that in normal membranes. ANP dose-dependently inhibited adenylate cyclase stimulated by GTP gamma S in control rat parotid membranes, however in membranes prepared from PT-injected (in vivo) rat parotid gland, ANP did not inhibit adenylate cyclase. ANP(10(-7)M) inhibited cAMP accumulation stimulated by forskolin (10(-6)M) in control rat parotid acinar cells by about 34%, however, in PT-treated cells, the inhibitory effect of ANP was attenuated completely. In control cells amylase release stimulated by isoproterenol (10(-6)M) and forskolin (10(-6)M) were also depressed by ANP (10(-7)M) by 27 and 30% respectively. The inhibitory response of ANP on amylase release was completely attenuated by PT-treatment. Gi was detected as a ADP-ribosylated 41-KDa protein by incubation of parotid membranes with PT and [alpha-32P]NAD. In rat parotid gland, these results suggested that ANP mediates adenylate cyclase/cAMP system and consequently reduces amylase release through ANP-C receptor coupled to Gi.
Shimomura
H
H
Department of Oral Biochemistry, Nippon Dental University, School of Dentistry, Niigata, Japan.
Nashida
T
T
Imai
A
A
D000246:Adenosine Diphosphate Ribose; D037361:Adenylate Cyclase Toxin; D000067956:Adenylyl Cyclase Inhibitors; D000262:Adenylyl Cyclases / Q000378:metabolism; D000681:Amylases / Q000378:metabolism*; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D005576:Colforsin / Q000494:pharmacology; D004789:Enzyme Activation; D019204:GTP-Binding Proteins / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D010306:Parotid Gland / Q000187:drug effects* / Q000201:enzymology; D037342:Pertussis Toxin; D051381:Rats; D017208:Rats, Wistar; D017461:Receptors, Atrial Natriuretic Factor / Q000378:metabolism; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
D037361:Adenylate Cyclase Toxin; D000067956:Adenylyl Cyclase Inhibitors; D010566:Virulence Factors, Bordetella; D005576:Colforsin; D000246:Adenosine Diphosphate Ribose; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D009320:Atrial Natriuretic Factor; D037342:Pertussis Toxin; D000681:Amylases; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases; D017461:Receptors, Atrial Natriuretic Factor; D007545:Isoproterenol