| Variable | Description |
| V | Volume (L) |
| G | Glucose concentration (mg/dL) |
| I | Insulin concentration (mU/dL) |
| Q | Vascular blood flow (dL/min) |
| Subscript | Description |
| H | Heart and Lungs |
| L | Liver |
| T | Tissues |
| A | Hepatic Artery |
| PIR | Peripheral insulin release |
| Superscript | Description |
| G | Glucose |
| I | Insulin |
| Constant to be estimated | Description |
| R | Metabolic source |
|
| or sink rate (mg/min or mU/min) |
| γ | Vascular blood flow rate (dL/min) |
| α | Parameter |
| β | Parameter |