Cortistatin-29 is a neuropeptide that is structurally similar to somatostatin-28. It is produced by cleavage of preprocortistatin to procortistatin, which is cleaved at dibasic amino acids to form cortistatin-29 and cortistatin-14 as well as other partial cleavage products. Cortistatin mRNA is expressed in the human brain and in interneurons of the rat hippocampus and cerebral cortex. Cortistatin-29 binds to somatostatin (SST) receptors with IC50 values of 2.8, 7.1, 0.2, 3, and 13.7 nM for SST1-5, respectively. Cortistatin-29 is found at similar levels as cortistatin-14 in mouse AtT20 cells but is secreted at a lower level. Cortistatin-29 corresponds to residues 85-112 of the rat peptide sequence.
Veldoreotide, also known as Somatoprim, is a unique somatostatin receptor subtypes 2-, 4- and 5-selective analogue which effectively reduces GH secretion in human GH-secreting pituitary adenomas, even in Octreotide non-responsive tumours.
L-803087 TFA is a highly potent and selective agonist of the somatostatin sst4 receptor, exhibiting a Ki value of 0.7 nM. It displays a remarkable selectivity, being over 280-fold more preferential for the sst4 receptor compared to other somatostatin receptors. Furthermore, L-803087 TFA promotes AMPA-mediated synaptic responses in hippocampal preparations and enhances kainate-induced seizures in mice.
CYN 154806 is a potent and selective somatostatin sst2 receptor antagonist, The pIC50 values are 8.58, 5.41, 6.07, 5.76 and 6.48 for human recombinant sst2, sst1, sst3, sst4 and sst5 receptors respectively.