TABLE 1

Nomenclature and properties of somatostatin receptors

	SST₁	SST₂	SST₃	SST₄	SST₅
Gennomic location	14q13	17q24	22q13.1	20p11.2	16p13.3
Amino acids	391	369	418	388	364
Naturally occurring agonists	SRIF-14, SRIF-28	SRIF-14, SRIF-28	SRIF-14, SRIF-28	SRIF-14, SRIF-28	SRIF-14, SRIF-28
Naturally occurring agonists	CST-17, CST-29	CST-17, CST-29	CST-17, CST-29	CST-17, CST-29	CST-17, CST-29
G protein coupling	Gα_i/o	Gα_i/o	Gα_i/o	Gα_i/o	Gα_i/o
Primary signal transduction	cAMP↓	cAMP↓	cAMP↓	cAMP↓	cAMP↓
	VOCC ↓	VOCC ↓	VOCC ↓	VOCC ↓	VOCC ↓
	GIRK↑	GIRK↑	GIRK↑	GIRK↑	GIRK↑
	NHE1↓	PTP↑	NHE1↓	NHE1↓	PTP↑
	PTP↑		PTP↑	PTP↑
Expression in human normal tissue	Brain	Brain	Brain	Brain
	Anterior pituitary Pancreatic islets	Anterior pituitary	Anterior pituitary	Retina	Anterior pituitary
	Gastrointestinal tract	Pancreatic islets	Pancreatic islets	Dorsal root ganglia	Pancreatic islets
		Dorsal root ganglia	Gastrointestinal tract	Placenta	Gastrointestinal tract
		Gastrointestinal tract	Lymphatic tissue		Lymphatic tissue
		Lymphatic tissue	Adrenals		Adrenals
		Adrenals
Expression in human tumors^{^a}	GH-Adenomas NET	GH-Adenomas	GH-Adenomas		GH-Adenomas
		TSH-Adenomas	ACTH-Adenomas		ACTH-Adenomas
		NET	NF-Adenomas		NET
		Pheochromocytomas
		Paragangliomas
Phenotype of mice lacking receptor	Altered insulin homeostasis	High basal acid secretion	Impaired novel object recognition	Increased seizure susceptibility	Increased insulin secretion
		Inhibition of glucagon release		Increased anxiety	Basal hypoglycemia
		Impaired motor coordination