Proinsulin human

Summary

Human proinsulin is the single-chain precursor molecule to insulin, secreted by pancreatic beta cells and normally converted to insulin and C-peptide before or upon secretion. Small amounts enter the circulation intact. It is used as a biomarker for beta-cell function and as a research tool. Elevated circulating proinsulin is associated with beta-cell stress, type 2 diabetes, and insulinoma. It is not approved as a therapeutic agent, though historical investigational use occurred.

Mechanism of Action

Proinsulin is the biosynthetic precursor of insulin, consisting of the B chain, C-peptide, and A chain connected in a single polypeptide. It has low intrinsic biological activity (~5% of insulin potency) and binds insulin receptors with reduced affinity. It is processed by prohormone convertases (PC1/3 and PC2) and carboxypeptidase E in pancreatic beta-cell secretory granules to yield mature insulin and C-peptide.

Routes of Administration

Goals & Uses

• Investigational hypoglycemic agentTherapeutics / MetabolicLow
• Research tool for insulin biosynthesisBasic ResearchHigh
• Insulinoma diagnosisDiagnostics / OncologyHigh
• Biomarker of beta-cell functionDiagnostics / EndocrinologyHigh

Contraindications

• Insulin hypersensitivityImmunologicHigh
• HypoglycemiaMetabolicHigh

Adverse Effects

• HypoglycemiaMetabolicUncommonAbnormally low blood glucose
• Injection site reactionsLocalUncommon
• Immunogenicity / antibody formationImmunologicUnknown

Drug Interactions

• SulfonylureasModerateMay increase risk of low blood sugar
• Insulin and insulin analoguesModerate

Population Constraints

• PregnancyReproductive SafetyRelative
• Renal impairmentOrgan ImpairmentRelative
• Pediatric populationsAgeRelative

Regulatory Status

• European UnionUnapprovedNot approved by EMA. Used as a laboratory diagnostic marker and research tool only.
• United StatesUnapprovedNot approved by FDA for any therapeutic indication. Used as a research reagent and diagnostic biomarker. IND-level investigational studies have been conducted historically.
• United KingdomUnapprovedNot approved by MHRA for therapeutic use. Diagnostic assays for serum proinsulin are available through NHS laboratories.

Not approved as a therapeutic drug by FDA, EMA, or MHRA. Used primarily as a diagnostic biomarker and research reagent. Recombinant human proinsulin has been studied in experimental settings but no therapeutic product is currently approved. Biosynthetic proinsulin (Eli Lilly) was an early investigational product in insulin production pipelines.

Evidence & Sources

No sources recorded yet.