The effects of gastrin on the ultrastructure of rat stomach endocrine cells

The effects of a single injection of gastrin on rat gastric endocrine cells were examined ultrastructurally and as a corollary serum gastrin was measured by radioimmunoassay. Eight fasting inbred rats received single subcutaneous injections of Pentagastrin (300 μg/kg) over a period of 24 hr. Gastric mucosa and blood were obtained from the rats which were sacrificed from 15 min to 24 hr after gastrin administration. At 30 min, serum gastrin was elevated to a peak of 321 pg/ml. ECL cells showed ultrastructural evidence of histamine release at 15 and 30 min. Somatostatin D and ECL cells both showed exocytotic figures at the same times. Evidence of granule release was rarely seen in the EC cells and hardly ever found in the G and A-like (or X) cells.