Mechanism of Action
Preferential SSTR5 Activation
SS-28 binds SSTR1-5 but shows significantly higher affinity for SSTR5 compared to SS-14. SSTR5 is highly expressed in pancreatic beta-cells and gut endocrine cells. This SSTR5 preference makes SS-28 a more potent inhibitor of postprandial insulin secretion than SS-14 at equivalent concentrations, contributing to blood glucose regulation during meal absorption.
GI Hormone Inhibition
SS-28 released from intestinal D-cells after meals inhibits secretin, CCK, GIP, and GLP-1 secretion in a paracrine manner. This broad inhibition of nutrient-stimulated gut hormones modulates the rate of intestinal absorption and pancreatic secretion. SS-28 is thus a key brake on postprandial incretin responses.
Research Summary
Incretin Modulation
PreclinicalSS-28 is a more potent inhibitor of GLP-1 secretion from L-cells than SS-14. In the context of GLP-1-based therapies, SS-28 receptor activation represents an endogenous brake on incretin action. SSTR5 antagonists that block SS-28 effects could potentially enhance endogenous GLP-1 release, offering an oral approach to incretin-based diabetes therapy.
SSTR5 Pharmacology
ClinicalSSTR5-selective analogs developed to understand SS-28 biology include L-817,818 and other research compounds. SS-28 has been used to characterize SSTR5 expression in pancreatic NETs, which often overexpress SSTR5. The differential expression of SSTR subtypes in NET subtypes guides somatostatin analog selection for treatment.
Calculate your Somatostatin-28 dose Vial strength, BAC water, exact syringe draw in IU. Free, no signup. Open Calc →
Research Protocols
| Goal | Dose | Frequency | Route |
|---|---|---|---|
| SSTR5 binding characterization | 0.1-100 nM | Single | Binding assay |
| Insulin suppression | 1-10 nM | Single | Islet incubation |
SS-28 is a research tool and endogenous hormone. Clinical use references somatostatin analogs (octreotide, pasireotide).
Interactions
Safety Profile
SS-28 is an endogenous GI hormone with a short plasma half-life. It shares the safety profile of somatostatin: risk of hypoglycemia (via insulin suppression at therapeutic doses), malabsorption, and gallstone formation with prolonged exposure. Clinical somatostatin analogs provide the relevant safety reference.
References
- [1]Patel YC (1999). Somatostatin and its receptor family. Frontiers in Neuroendocrinology, 20(3), 157-198.
- [2]Chessler SD et al. (2000). The regulation of somatostatin-28 versus somatostatin-14 processing by the SSTR5 receptor. Journal of Molecular Endocrinology, 24(2), 267-276.