AJP - Gastrointestinal and Liver Physiology, Vol 254, Issue 2 217-G223, Copyright © 1988 by American Physiological Society
Somatostatin inhibits VIP-stimulated amylase release from perifused guinea pig pancreatic acini
P. Singh, I. Asada, A. Owlia, T. J. Collins and J. C. Thompson
Department of Surgery, University of Texas Medical Branch, Galveston 77550.
We have examined the direct effect of somatostatin (SRIF) on basal and
stimulated amylase release from guinea pig pancreatic acini using the in
vitro method of continuous perifusion. The optimal conditions of flow rate,
chamber size, acinar cell volume per chamber, and period of secretagogue
infusion were defined for the perifusion system. The kinetic profile of
amylase release in response to cholecystokinin-octapeptide (CCK-8),
vasoactive intestinal peptide (VIP), and SRIF was studied. Under optimal
conditions, the acini were found to remain equally responsive to an ED50
dose of CCK-8 (0.5-0.8 nM) for 12 h of perifusion. The duration of amylase
response to any given dose of CCK-8, given for the optimal period of 5 min,
was 80-100 min. The total amylase released minus the basal release divided
by 90 min (delta response) in response to the maximum effective (Maxeff)
dose of CCK-8 (100 nM) was 14,667 +/- 1,433 U/l (amounting to a 10-fold
increase compared with basal values). When compared with the amount of
total delta amylase released in response to the Maxeff dose of CCK, the
total amylase released in response to the Maxeff doses of SRIF (1 microM)
and VIP (10 nM) was 10-21% and 51-59%, respectively. SRIF (100 nM)
significantly decreased VIP- (0.1-1.0 nM) stimulated amylase release by
45-70% in the perifusion method of study but had no significant effect on
the CCK-stimulated amylase release. This suggests that the perifusion
method can be used for investigating the mechanism of SRIF-mediated
inhibition of VIP effects on amylase release in an in vitro system.
