Uptake of 3H-GABA (gamma-aminobutyric acid) and 3H-leucine in the pancreatic islets and substantia nigra of the rat.

Isolated pancreatic islets and thin slices of substantia nigra (SN) of the rat were incubated in a medium containing 3H-GABA or 3H-leucine to test the activity of both tissues in the uptake of those substances. Pancreatic islets showed a low uptake of both 3H-GABA and 3H-leucine, but SN had a high activity in the uptake of 3H-GABA, though not for 3H-leucine. This suggests that GABA contained at high levels in the pancreatic islets some functional role other than in neurotransmission as in the central nervous system (CNS).