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

The somatostatin receptor subtype sst2 was visualized by immunostaining on cultivated rat astrocytes and C6 rat glioma cells. Octreotide, a metabolically stable sst2 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 sst2 receptors may be desensitized. Thus, desensitization might hinder application of octreotide to reduce glial tumour growth.