Involvement of Ca2+ influx in F(-)-stimulated pepsinogen release from guinea pig gastric chief cells.
In isolated guinea pig gastric chief cells, pepsinogen release was stimulated by NaF in a dose-dependent manner. Cholecystokinin (CCK) and Ca2+ ionophore A23187 had no additional effect on NaF-stimulated pepsinogen release. CCK caused a rapid increase in intracellular free Ca2+ concentration ([Ca2+]i) monitored by Quin-2 and markedly stimulated inositol phosphate accumulation in chief cells. By contrast, NaF did not cause any change in [Ca2+]i. NaF, even at a maximal concentration for pepsinogen release, appeared to be relatively ineffective on inositol phosphate accumulation. On the other hand, NaF markedly stimulated Ca2+ influx into chief cells. These results suggest that F- stimulates pepsinogen release probably by increasing Ca2+ influx into chief cells. Since F- is a well known activator of guanine nucleotide regulatory proteins (G proteins), it is proposed that there may exist a G protein regulating the opening of Ca2+ channel in gastric chief cells.
Matozaki
T
T
Second Department of Internal Medicine, Kobe University School of Medicine, Japan.
Sakamoto
C
C
Nagao
M
M
Nishizaki
H
H
Konda
Y
Y
Baba
S
S
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D005753:Gastric Mucosa / Q000187:drug effects / Q000378:metabolism*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007700:Kinetics; D010435:Pepsinogens / Q000378:metabolism*; D012633:Secretin / Q000494:pharmacology; D012844:Sincalide / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology*
D010435:Pepsinogens; D012633:Secretin; D000001:Calcimycin; D012965:Sodium Chloride; D000242:Cyclic AMP; D012844:Sincalide; D002118:Calcium