Octapeptide somatostatin-analogue therapy of Cushing's syndrome

The currently available octapeptide somatostatin analogues octreotide (Sandostatin, Sandostatin LAR, Novartis, Basle, Switzerland) and somatuline (BIM 23014, Lanreotide, Beaufort-Ipsen, Paris, France) have beneficial effects in the treatment of various neuroendocrine tumour syndromes. These effects are mediated through specific membrane-associated somatostatin receptor subtypes (ssts) on the target tissues.1 Five different sst subtypes (sst_1–5) have been cloned and characterised, and it was demonstrated that octapeptide somatostatin analogues bind with a high affinity to sst₂ and sst₅, show a low affinity to sst₃, but no affinity to sst₁ and sst₄.1 Tumours and metastases, which bear receptors for octapeptide analogues, can be visualisedin vivo using gamma camera pictures obtained after injection of ¹¹¹In-pentetreotide (OctreoScan, Mallinckrodt, Petten, The Netherlands).1

The possible therapeutic effects of octreotide have been studied in the different subclasses of Cushing's syndrome. Cushing's disease, which exclusively stands for the excessive secretion of (adreno)corticotropin (ACTH) by the pituitary, is the main variant of Cushing's syndrome, representing about …