Glucose-Insulin Homeostasis Simulator: Blood Sugar Regulation Model

simulator intermediate ~10 min
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Fasting glucose ≈ 90 mg/dL with normal insulin sensitivity and beta-cell function

With standard parameters (glucose intake 8, sensitivity 1.0, 100% beta-cell function, hepatic output 2), fasting glucose stabilizes near 90 mg/dL. After a glucose bolus, the level peaks around 140 mg/dL and returns to baseline within approximately 120 minutes — a normal glucose tolerance curve.

Formula

dG/dt = glucose_input + hepatic_output - insulin_sensitivity * I * G / G_ref
dI/dt = beta_cell_function * max(0, G - G_threshold) / 100 - clearance_I * I
Fasting glucose ≈ hepatic_output / (sensitivity * beta_function)

Blood Glucose Regulation

The human body maintains blood glucose within a narrow range of 70-100 mg/dL despite enormous variation in food intake and energy expenditure. This homeostasis is achieved through a coordinated interplay between insulin (which lowers glucose) and counter-regulatory hormones like glucagon (which raises it). The pancreatic beta cell serves as the glucose sensor and insulin secretion engine at the center of this regulatory system.

The Minimal Model of Glucose Kinetics

This simulator implements a simplified version of the Bergman Minimal Model, one of the most widely used mathematical frameworks in diabetes research. Glucose dynamics are governed by two competing fluxes: glucose appearance (dietary input plus hepatic production) and glucose disappearance (insulin-mediated uptake plus basal clearance). Insulin secretion is proportional to glucose elevation above a threshold, scaled by beta-cell capacity.

Modeling Diabetes

Type 2 diabetes develops through a progression of insulin resistance followed by beta-cell failure. Start by reducing insulin sensitivity to 0.3 — you'll see compensatory hyperinsulinemia maintaining near-normal glucose. Then reduce beta-cell function below 50% to observe the transition to frank hyperglycemia. For Type 1, set beta-cell function to 10-20% to model near-complete insulin deficiency.

Clinical Implications

The glucose tolerance test (GTT) is the clinical gold standard for diagnosing diabetes. This simulation produces curves directly comparable to GTT results. Watch how the parameters affect fasting glucose, peak postprandial excursion, and time to return to baseline. The area under the insulin curve reflects total insulin secretion — elevated AUC with normal glucose suggests compensated insulin resistance.

FAQ

How does insulin regulate blood glucose?

Insulin is secreted by pancreatic beta cells in response to rising blood glucose. It promotes glucose uptake by muscle and fat cells, stimulates glycogen synthesis in the liver, and suppresses hepatic glucose production. This combined action lowers blood glucose back toward the fasting set point of approximately 70-100 mg/dL.

What is insulin resistance?

Insulin resistance occurs when cells respond less effectively to insulin. Higher insulin levels are needed to achieve the same glucose-lowering effect. Over time, beta cells may fail to compensate, leading to elevated blood glucose and eventually Type 2 diabetes.

What is the difference between Type 1 and Type 2 diabetes?

Type 1 diabetes results from autoimmune destruction of beta cells, causing near-zero insulin production. Type 2 diabetes begins with insulin resistance and progresses through beta-cell dysfunction. In this simulator, reduce beta_cell_function to model Type 1, and reduce insulin_sensitivity for Type 2.

What is a normal postprandial glucose level?

In healthy individuals, blood glucose peaks at 140 mg/dL or less within 1-2 hours after eating and returns to fasting levels within 3 hours. Values exceeding 200 mg/dL at 2 hours indicate diabetes.

Sources

Embed

<iframe src="https://homo-deus.com/lab/endocrinology/insulin-glucose/embed" width="100%" height="400" frameborder="0"></iframe>
View source on GitHub