The glucose homeostat

Euglycemia is a defended R19 attractor on the insulin-glucose node. A glucose load displaces the state; the insulin loop returns it to the setpoint (True). The same defended-basin logic that pins body temperature pins blood glucose -- one substrate, two regulated variables. The ~5 mM set value is cited.

RE1. Whole-body glucose control is the temperature thermostat in another variable: a regulated attractor that opposes displacement. Mechanism [V]; the euglycemic setpoint (~5 mM) is [L]; the absolute glucose excursion in mg/dL is [O].

Load and return

Starting at the euglycemic setpoint (1.2229 in R19 units), a positive load is corrected back (True). This is the homeostatic baseline whose FAILURE the type-2-diabetes chapter describes as a loop-gain drop.

Why glucose belongs in a thermometabolic map

Temperature and fuel are defended by the same control architecture, and they are coupled -- the torpor fuel-switch (PDK4) sits between them. Treating glucose as one more defended setpoint is what lets the hibernation-bridge chapter connect torpor to insulin resistance.