The effect of intraislet somatostatin immunoneutralization on insulin secretion in the isolated perfused rat pancreas.
BACKGROUND
There is evidence of a local inhibitory effect of somatostatin on insulin secretion in the isolated human pancreas, but this has not been shown in a rat model. The possible phasic effect of somatostatin on insulin secretion has not been demonstrated.


OBJECTIVE
This study was undertaken to determine if somatostatin has a local regulatory effect on phasic insulin secretion within a rat pancreas model.


METHODS
The basal and glucose stimulated secretion of insulin was compared with and without immunoneutralization of somatostatin using a somatostatin antibody in an isolated perfused rat pancreas model. High concentration, high affinity monoclonal somatostatin antibody was perfused through isolated rat pancreata. Radioimmunoassay for insulin was performed on the portal effluent.


RESULTS
Immunoneutralization of somatostatin during basal insulin secretion produced a rise in insulin secretion of 551 +/- 163% that approached significance. Immunoneutralization during glucose stimulated insulin secretion produced a significant rise in insulin secretion compared to the control group of 2,678 +/- 187% vs. 535 +/- 39% (p < 0.05). The phase I vs. the phase II response in the glucose stimulated pancreas was similar in the presence of control antibody, 867 +/- 351% vs. 900 +/- 398% (p = NS). With somatostatin immunoneutralization, the glucose stimulated pancreas had a significantly higher phase II response than phase I; 3,832 +/- 688% vs. 2,516 +/- 431% (p < 0.05).


CONCLUSIONS
These data indicate that intraislet somatostatin is an inhibitor of insulin secretion in the isolated perfused rat pancreas. This effect occurs primarily in phase II of insulin secretion.
Brunicardi
F C
FC
Department of Surgery, Baylor College of Medicine, Houston, TX 77030, USA.
Wen
D
D
Bradley
J C
JC
Elahi
D
D
Miller
C
C
Hanks
J
J
D000818:Animals; D000906:Antibodies / Q000276:immunology*; D005947:Glucose / Q000494:pharmacology; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism*; D008297:Male; D010179:Pancreas / Q000378:metabolism*; D010477:Perfusion; D051381:Rats; D011917:Rats, Inbred Lew; D013004:Somatostatin / Q000276:immunology*
D000906:Antibodies; D007328:Insulin; D013004:Somatostatin; D005947:Glucose