Ultrastructure of avian gastrin cell granules

Gastrin cells in the pigeon, quail, gull and kite were identified at ultrastructural level by immunocytochemistry, using the consecutive semithin/ultrathin section technique. In contrast to the gastrin granules known in mammals, the avian gastrin granules generally contained a consistent dense core accompanied by a clear halo between the core and limiting membrane. The mean diameters of gastrin granules in the pigeon, quail, gull and kite were 211 +/- 37, 247 +/- 45, 331 +/- 61 and 353 +/- 73 nm respectively. The carnivorous birds seemed to possess larger gastrin granules than the grain-eating birds. The species differences in the size and fine structures of the gastrin granules were discussed.