Effects of delays in a nonlinear glucose-insulin feedback system
René Normann Hansen
Scientific Computing, Novo Nordisk A/S, Novo Nordisk Park,
2760 Måløv, Denmark
Department of Physics, Technical University of Denmark,
2800 Kongens Lyngby, Denmark
The insulin-mediated effect on plasma glucose is somehow delayed.
Moreover, in diabetics insulin production and resistance may represent
additional delays in the action of insulin. In order to establish the
effects of delays on plasma glucose and insulin, various delays were
put into a physiology-based nonlinear model for blood glucose regulation.
Using linear stability analysis it was found that the model under most
conditions exhibited dampened oscillations. Depending on the magnitude
and actual placement of delays in the model the period of oscillation
could be brought into a range of physiological interest. This finding
could have importance in the treatment of diabetes where the effect of
insulin shots may be modulated according to the dampened oscillations
of the body's own level of plasma glucose and insulin.