Time-dependent influence of the somatostatin analogue octreotide on the proliferation of rat astrocytes and glioma cells

The somatostatin receptor subtype sst 2 was visualized by immunostaining on cultivated rat astrocytes and C6 rat glioma cells. Octreotide, a metabolically stable sst 2 agonist reduced [ 3H]thymidine incorporation into DNA of both cell types dose-dependently only after short-time application (2–5 h), after prolonged incubation (>12 h) no antiproliferative effect was measurable. We conclude that sst 2 receptors may be desensitized. Thus, desensitization might hinder application of octreotide to reduce glial tumour growth.