Modeling the effect of blood glucose and physical exercise on plasma adrenaline in people with type 1 diabetes.
BACKGROUND
Adrenaline is often studied in people with type 1 diabetes during hypoglycemic episodes. Adrenaline is difficult and costly to measure, and therefore a pharmacokinetic model of adrenaline can be a supportive tool that adds information and saves measurements resources.


METHODS
We have developed a compartment model of adrenaline secretion and elimination. It is based on input on physical exercise, blood glucose level, and optional infused adrenaline. The model parameters are identified using least square regression on published data of adrenaline kinetics measured in a number of different clinical studies.


RESULTS
Simulation of published adrenaline measurements shows agreement with data of adrenaline infusion (R(2) = 0.9), exercise (R(2) = 0.97), and hypoglycemic episodes (R(2) = 0.93-0.97). The identified function describing adrenaline secretion during hypoglycemia shows an exponential increase for a blood glucose decreasing below 3.5 mmol/L and an approaching maximum around 1 mmol/L. Exercise intensity increasing above 50% of maximal oxygen uptake maximum causes approximately exponential increase in adrenaline secretion.


CONCLUSIONS
The model is a simple tool that can be used to simulate and predict adrenaline concentrations in situations of hypoglycemia, physical exercise, and adrenaline infusion. In conclusion, the developed model, although simple, seems to be useful for simulating adrenaline dynamics in situations with hypoglycemic episodes, physical exercise, or infusion.
Kildegaard
Jonas
J
Department of Health Science and Technology, University of Aalborg, Aalborg, Denmark. mail@jonaskildegaard.com
Christensen
Toke Folke
TF
Johansen
Mette Dencker
MD
Randløv
Jette
J
Hejlesen
Ole K
OK
D001786:Blood Glucose / Q000378:metabolism*; D003198:Computer Simulation; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D004837:Epinephrine / Q000097:blood*; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007003:Hypoglycemia / Q000378:metabolism; D008954:Models, Biological
D001786:Blood Glucose; D004837:Epinephrine