Gamma-Aminobutyric Acid in Peripheral Tissue, with Emphasis on the Endocrine Pancreas: Presence in Two Species and Reduction by Streptozotocin

A screen of selected periphral organs of the rat found that gamma-aminobutyric acid (GABA) is generally present outside the central nervous system, and, of those organs examined, GABA was present at the highest concentration in the pancreas (approximately 40 pmol/mg wet wt). Furthermore, this putative inhibitory neurotransmitter was found to be present at even higher levels in islets of Langerhans tissue isolated from rat pancreas (190 pmol/mg). Administration of streptozotocin, a selective beta-cell toxin, decreased pancreatic GABA levels significantly, but had no or only small effects on the GABA content of other organs. Normal teleost (catfish) Brockmann body contains about the same level of GABA as normal rat islet tissue.