Modulation of somatostatin binding sites in cytosol of rabbit gastric fundic mucosa by cysteamine administration.

Cysteamine, when given in vivo to rabbits, depleted immunoreactive somatostatin in rabbit gastric fundic mucosa. Depletion of immunoreactive somatostatin was associated with both an increase in the number and a decrease in the affinity of the low-affinity somatostatin binding sites. The in vitro incubation of cysteamine (0.1 mM) with the cytosolic fraction did not result in any modification of somatostatin binding. These results suggest that a decrease in the endogenous immunoreactive somatostatin might lead to up-regulation of somatostatin binding sites in the gastric fundic mucosa.