AJP - Endocrinology and Metabolism, Vol 261, Issue 4 E444-E456, Copyright © 1991 by American Physiological Society
Neuronal influence on hormone release from anglerfish islet cells
S. L. Milgram, J. K. McDonald and B. D. Noe
Department of Anatomy and Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322.
Pancreatic islets in anglerfish (AF) are macroscopic collections of nearly
pure endocrine cells that are densely innervated. Immunohistochemical
staining for neurotransmitter biosynthetic enzymes revealed noradrenergic
and cholinergic innervation of AF islets. An in vitro preparation of
perifused dispersed AF islet cells was developed to study nutrient and
neural control of islet hormone secretion. Glucose stimulated insulin and
somatostatin-14 (SS-14) secretion in a dose-dependent manner, and 16.7 mM
glucose inhibited glucagon secretion. In 2 mM glucose, norepinephrine and
isoproterenol stimulated glucagon and SS-14 release. Isoproterenol
stimulated insulin secretion, and norepinephrine stimulated or inhibited
insulin release, depending on the concentration. Clonidine potently
inhibited glucose-stimulated insulin secretion but stimulated glucagon
release. Methacholine, a muscarinic cholinergic agonist, stimulated
insulin, glucagon, and SS-14 release. The control of AF hormone release by
neurotransmitter agonists in vitro was similar to that in higher vertebrate
species. Therefore we used this tissue preparation to study postsynaptic
interactions between glucose and neurotransmitters in islets.
