somatostatiini28

Somatostatiini28, also known as somatostatin-28 (SST-28), is a peptide hormone consisting of 28 amino acids and one of the major active forms of somatostatin in humans. It originates from the proteolytic processing of the precursor preprosomatostatin, alongside the shorter somatostatin-14.

Distribution and production vary by tissue. SST-28 is primarily produced by enteroendocrine cells in the gastrointestinal tract and pancreatic D cells, contributing to gut- and pancreas-related regulation. In contrast, the hypothalamus largely contains the shorter somatostatin-14 form, which plays a central role in inhibiting growth hormone release from the pituitary. Both forms are found in various tissues and can be released into local (paracrine/autocrine) or systemic circulation.

Mechanism of action and role. Somatostatin peptides exert broad inhibitory effects on endocrine and exocrine secretions. They bind to somatostatin receptors (SSTR1–SSTR5), a family of G protein-coupled receptors, leading to reduced cAMP levels, inhibited calcium influx, and suppression of hormone secretion. SST-28 and SST-14 differ in their tissue distribution and receptor-binding profiles, which contributes to distinct physiological roles. SST-28 is often associated with gut-related regulation, including inhibition of certain gastrointestinal hormone secretions and modulation of intestinal motility, whereas SST-14 is more closely linked to hypothalamic-pituitary control of growth and metabolism.

Clinical relevance. Endogenous somatostatin signaling is mimicked therapeutically by somatostatin analogs such as octreotide and lanreotide, used in the treatment of acromegaly and neuroendocrine tumors. In research and clinical contexts, SST-28 can be measured to study gut and pancreatic endocrine regulation, contributing to understanding of hormonal balance and digestive physiology.