liver-glycogen-model

Code from the paper: Xu K, Morgan KT, Todd A, Elston TC and Gomez SM. A whole-body model for glycogen regulation reveals a critical role for substrate cycling in maintaining blood glucose homeostasis. PLoS Computational Biology. 2011. Dec;7(12):e1002272.

How to Run Liver_glycogen_model:

1. Open runmain.m under MATLAB editor and click on ‘run’ button; or type ‘runmain’ in the command window.
2. In runmain.m, two functions are called: main.m is the main program file and plot_conc.m is the plot function for generating enzyme (glycogen synthase a and glycogen phosphorylase a) and substrate (glycogen) concentrations over time. The four concentrations 0.2 mM/min, 0.4 mM/min, 0.6 mM/min and 1.4 mM/min are consistent with those presented in our paper.
3. main.m takes two inputs: state and gluc_input. state takes the value of fed or fasted, which determines the fasting time from fed steady state. There are 3 runs in main.m: the first run is for the system to reach fed steady state with a constant feeding rate in the blood; the second run is the post-adsorption state with a decreasing glucose feeding rate from the fed steady state (drops below 5% in 140 mins.) Here, two fasting times are chosen to represent a fed and fasted livers: tmax = 250 mins or tmax = 1200 mins. The third run is for a glucose stimulus to enter the system as a step function. This rate is stored in the input variable gluc_input.
4. plot_conc.m generates figures for GPa, GSa and glycogen after the glucose stimulus enters the system.
5. Data are stored in the folder ‘./results’ in the form of y_fasted_XpX.mat or y_fed_XpX.mat where XpX is the glucose feeding rate in the blood. For example, y_fasted_0p2.mat means glucose input rate = 0.2 in a fasted liver.