Identification and characterization of a type five-like somatostatin receptor in goldfish pituitary

Abstract

In this study, a somatostatin receptor (Sst) cDNA was cloned and sequenced from goldfish pituitary. The cDNA encodes a 390-amino acid type five-like Sst (designated as gfSst5). The amino acid sequence of the receptor has slightly higher homology to mammalian Sst5′, compared with other mammalian Sst subtypes and recently identified fish Sst1, Sst2 and Sst3. In CCL39-SRE-Luci cells stably expressing the cloned receptor, agonist radioligand [125I]LTT-SRIF28′, a mammalian SRIF28 analog, bound to a homogenous population of receptors with high affinity (nM Kd). Competition binding studies showed that all three natural goldfish SRIF ligands, SRIF14, [Pro2]SRIF14, and goldfish SRIF28 (gfSRIF28), and..