In vitro inhibitory effect of somatostatin on secretin action in exocrine pancreas of rats.
BACKGROUND
Exocrine pancreatic function is influenced by pancreatic islet hormones. Although the existence of somatostatin receptors has been shown on pancreatic acinar cells, the in vitro effect of somatostatin on exocrine secretory function has not been established.


METHODS
Using isolated rat pancreatic acini, the effect of somatostatin analog SMS 201-995 (SMS) and somatostatin 14 (S-14) on amylase release, cyclic adenosine monophosphate (cAMP) production, and hormone binding were determined.


RESULTS
SMS inhibited the potentiating effect of secretin on amylase response to cholecystokinin octapeptide (CCK-8) in a concentration-dependent manner. The inhibitory effects of SMS and S-14 were similar on a molar basis and were observed when vasoactive intestinal polypeptide (VIP) but not 8bromoadenosine 3':5' cyclic monophosphate was used instead of secretin and when carbachol, bombesin, A23187, and 12-O-tetradecanoylphorbol 13-acetate were used instead of CCK-8. SMS inhibited secretin-induced cAMP production, and the dose-inhibition curve for cAMP was similar to that for amylase release. SMS had no influence on 125I-secretin and 125I-VIP binding.


CONCLUSIONS
Somatostatin acts directly on acinar cells and inhibits secretin potentiation of secretory response in part by inhibiting secretin-induced cAMP production.
Matsushita
K
K
Second Department of Internal Medicine, Kobe University School of Medicine, Japan.
Okabayashi
Y
Y
Hasegawa
H
H
Koide
M
M
Kido
Y
Y
Okutani
T
T
Sugimoto
Y
Y
Kasuga
M
M
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000681:Amylases / Q000378:metabolism*; D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D015282:Octreotide / Q000494:pharmacology*; D010179:Pancreas / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D043562:Receptors, G-Protein-Coupled; D011964:Receptors, Gastrointestinal Hormone / Q000378:metabolism; D018005:Receptors, Vasoactive Intestinal Peptide; D012633:Secretin / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology*; D012844:Sincalide / Q000494:pharmacology; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism* / Q000494:pharmacology
D043562:Receptors, G-Protein-Coupled; D011964:Receptors, Gastrointestinal Hormone; D018005:Receptors, Vasoactive Intestinal Peptide; C029937:secretin receptor; D012633:Secretin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D014660:Vasoactive Intestinal Peptide; D000242:Cyclic AMP; D000681:Amylases; D012844:Sincalide; D015282:Octreotide