Gastrin I (human): Precision Regulator for Gastric Acid Secretion Pathway Research

Executive Summary: Gastrin I (human) is an endogenous peptide that stimulates gastric acid secretion by activating CCK2 receptors on parietal cells, with a molecular weight of 2098.22 Da and CAS number 10047-33-3 (ApexBio product B5358). It is water- and ethanol-insoluble but dissolves in DMSO at ≥21 mg/mL. The peptide is validated at ≥98% purity by HPLC and mass spectrometry, supporting reproducible in vitro modeling of gastric acid secretion and gastrointestinal physiology (Saito et al., 2025). Gastrin I (human) is critical for advanced organoid workflows and pharmacokinetic studies, particularly in the context of gastrointestinal disorder research (Contrast: precision modeling). Proper storage at -20°C, desiccated, is required for optimal stability and experimental fidelity.

Biological Rationale

Gastrin I (human) is an endogenous regulatory peptide secreted by G-cells in the gastric antrum. It is a principal physiological regulator of gastric acid secretion. Gastrin I binds to the cholecystokinin B receptor (CCK2R), predominantly expressed on gastric parietal cells, to stimulate acid production. This peptide also plays a role in mucosal growth and cellular differentiation within the gastrointestinal tract. Precise in vitro modeling of gastric acid regulation is essential for elucidating pathophysiological mechanisms underlying peptic ulcer disease, gastritis, and gastric neoplasia (Saito et al., 2025). Human pluripotent stem cell-derived organoids now permit high-fidelity recapitulation of gastrointestinal signaling pathways, with Gastrin I as a key effector in such systems (Contrast: organoid-based research).

Mechanism of Action of Gastrin I (human)

Gastrin I (human) exerts its biological effects by binding to the CCK2 receptor (also known as the gastrin/CCK-B receptor). This interaction occurs on the basolateral membrane of gastric parietal cells. Upon ligand binding, the receptor activates Gq/11 proteins, leading to phospholipase C (PLC) activation. PLC hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2) to generate inositol trisphosphate (IP3) and diacylglycerol (DAG). IP3 triggers Ca²⁺ release from intracellular stores, while DAG activates protein kinase C (PKC). The rise in cytosolic Ca²⁺ and PKC activity together increase H⁺/K⁺-ATPase (proton pump) activity, resulting in enhanced secretion of gastric acid (Extends: technical insights on pathway). This signaling cascade is rapid and reversible, forming the basis for acute regulation of gastric acid output in both physiological and experimental contexts.

Evidence & Benchmarks

• Gastrin I (human) stimulates dose-dependent gastric acid secretion in human and animal parietal cells in vitro (Saito et al. 2025, DOI).
• High-purity peptide (≥98%) is confirmed by HPLC and MS, ensuring batch-to-batch reproducibility (Product QC).
• Gastrin I-driven CCK2 receptor activation induces measurable Ca²⁺ flux within 1–3 minutes at 37°C in organoid-derived epithelial monolayers (Saito et al. 2025, DOI).
• Compatibility with hiPSC-derived intestinal organoid workflows has been demonstrated for pharmacokinetic and secretion pathway studies (DOI).
• Solubility in DMSO at concentrations ≥21 mg/mL enables high-concentration stock solutions for in vitro assays (Product documentation).

Applications, Limits & Misconceptions

Gastrin I (human) is employed as a gold-standard agonist in studies of gastric acid secretion, gastrointestinal physiology, and CCK2 receptor signaling. Its high stability and purity make it suitable for advanced organoid-based pharmacokinetic and disease modeling workflows. The peptide is also instrumental in dissecting receptor-mediated signal transduction in parietal and enteroendocrine cells (Updates: translational research).

Common Pitfalls or Misconceptions

• Gastrin I (human) is not soluble in water or ethanol and requires DMSO for preparation at experimental concentrations.
• It is specific to CCK2 receptors and does not activate CCK1 receptors or unrelated GPCRs.
• Long-term storage of peptide solutions leads to degradation; fresh aliquots should be prepared prior to each experiment.
• In vivo effects may differ from in vitro due to metabolic clearance and tissue-specific expression profiles.
• Gastrin I is not suitable as a substitute for non-peptidergic acid secretagogues (e.g., histamine or acetylcholine mimetics).

Workflow Integration & Parameters

For in vitro use, Gastrin I (human) should be reconstituted in DMSO at concentrations ≥21 mg/mL. Working solutions are prepared by further dilution in assay buffer immediately before use. The peptide should be stored desiccated at -20°C, and repeated freeze-thaw cycles should be avoided. For organoid or monolayer assays, typical exposure concentrations range from 1 nM to 1 μM, with exposure times from 5 to 60 minutes, depending on assay endpoints. Its compatibility with human iPSC-derived intestinal organoid systems makes it especially valuable for pharmacokinetic and secretion pathway studies (Saito et al., 2025). For detailed technical attributes and integration with next-generation GI physiology modeling, see this article (connects CCK2 signaling to organoid workflows).

Conclusion & Outlook

Gastrin I (human) is an indispensable tool for mechanistic studies of gastric acid secretion and receptor-mediated signal transduction. Its high purity, reproducibility, and compatibility with advanced cell models make it the benchmark standard for gastrointestinal physiology and pharmacokinetic research. As human stem cell-derived organoid systems become more prevalent, this peptide's role in translational GI disorder modeling and drug discovery will expand. For further technical specifications and ordering information, refer to the product page for Gastrin I (human).