Glucose–insulin homeostat setpoint

A glucose load returns to the ~5 mM setpoint via the insulin loop. Insulin secretion is a graded population of R19 switches activating as glucose rises; meals lift the peak from 5.9 to 11.1 mM, yet every load settles near 5.2 mM. Homeostatic return is forced by the closed loop [V]; the 5 mM setpoint is cited [L].

Insulin secretion is a graded population of R19 switches; the closed loop dG/dt = R_meal + HGP − (k_u0 + k_u·Ins)·G returns glucose to a 5.0 mM fixed point. Meal peaks from 5.9 to 11.1 mM all settle near 5.2 mM. Homeostasis is [V]; the 5 mM setpoint is [L].

A glucose load returns to the ~5 mM fasting setpoint through the insulin loop. The fasting fixed point sits at 5.0 mM; meals of increasing size lift the peak from 5.9 to 11.1 mM, yet every load settles back near 5.2 mM.

Insulin secretion is not a single threshold but a graded population of R19 switches: as glucose rises, progressively more β-cell switches turn on, giving a smooth dose-response that the loop integrates. Hepatic glucose production is suppressed by insulin and supported by a finite glycogen buffer, closing the loop dG/dt = R_meal + HGP − (k_u0 + k_u·Ins)·G.

Homeostatic return is forced by the closed loop [V]; the 5 mM setpoint value is a cited human fasting anchor [L]. The pancreas (PDX1) owns the secretion switches and the liver (HHEX) owns the glycogen buffer, so the homeostat is a two-organ control loop, not a single-organ device.