Insulin Metabolism and Clearance Mechanisms

Insulin metabolism encompasses the synthesis of proinsulin in pancreatic β-cells, its processing into mature hormone and C-peptide, and regulated release in response to glucose and incretin signals. Once in the circulation, insulin distributes between vascular and interstitial compartments, binding to its receptor on target cells to initiate signalling cascades that promote glucose uptake, lipid synthesis and protein anabolism. The primary route of insulin removal is receptor-mediated endocytosis in the liver, accounting for up to two-thirds of hormone extraction during its first pass. Secondary clearance occurs in the kidney, muscle and other peripheral tissues, where receptor binding and proteolytic degradation further limit insulin’s half-life. The interplay between secretion and clearance establishes steady-state plasma insulin concentrations critical for maintaining euglycaemia. Genetic variation or acquired defects in key mediators of uptake and degradation can reduce clearance, leading to hyperinsulinaemia and progressive insulin resistance. Dynamic modulation of clearance during feeding, developmental transitions such as puberty, and in pathological states including obesity or non-alcoholic fatty liver disease underscores its importance. Advances in mapping these mechanisms inform global strategies for diabetes prevention, optimisation of exogenous insulin therapy and identification of early biomarkers of metabolic dysfunction.

Research from Nature Portfolio

Recent analyses in healthy non-obese adults have clarified the early determinants of metabolic insulin clearance, demonstrating that lower clearance rates coincide with modest impairments in muscle insulin sensitivity, increased adiposity and reduced cardiorespiratory fitness. These findings indicate that diminished hepatic extraction may serve as an adaptive response to preserve glucose disposal when peripheral insulin action begins to falter, offering potential early markers of cardiometabolic risk.

Insulin Metabolism and Clearance Mechanisms publication trend

The graph below shows the total number of articles in insulin metabolism and clearance mechanisms across all publications each year (not limited to Nature Index journals).

Technical terms

Insulin clearance: The process by which circulating insulin is removed from the blood, primarily through receptor-mediated uptake and degradation.

Metabolic clearance rate (MCR): The volume of plasma from which insulin is completely removed per unit time.

First-pass hepatic extraction: The proportion of insulin extracted by the liver during its initial passage through the portal circulation after secretion.

Receptor-mediated endocytosis: Cellular uptake mechanism whereby insulin binds its receptor, triggering internalisation into endosomes and subsequent degradation.

CEACAM1: A hepatocyte glycoprotein that enhances insulin receptor complex uptake, promoting efficient hepatic clearance of the hormone.

References

1. Elevations in plasma glucagon are associated with reduced insulin clearance after ingestion of a mixed-macronutrient meal in people with and without type 2 diabetes. Diabetologia (2024).
2. Insulin Clearance at the Pubertal Transition in Youth with Obesity and Steatosis Liver Disease. International Journal of Molecular Sciences (2023).
3. Insulin Resistance Induced by Hyperinsulinemia Coincides with a Persistent Alteration at the Insulin Receptor Tyrosine Kinase Domain. PLOS ONE (2014).
4. Correlates of insulin clearance in apparently healthy non-obese Japanese men. Scientific Reports (2017).
5. Loss of Hepatic CEACAM1: A Unifying Mechanism Linking Insulin Resistance to Obesity and Non-Alcoholic Fatty Liver Disease. Frontiers in Endocrinology (2017).
6. Insulin Clearance in Health and Disease. Annual Review of Physiology (2022).