hepatomas). The oscillation period is around 12 h and 2 days,
depending on feeding conditions. The oscillations’ period shown
in the model is of the same order, despite that a different kind of
cancer cell line has been used.
It can be easily recognized that higher complexity states (and
consequently higher robustness states) are found at low Pi and Glu.
When Pi concentration is increased, the system reaches less complex
states. The zone in which periodic oscillations can be found grows
thinner with increasing Glu, while the opposite happens for stable
steady states. This finding reaffirms the hypothesis that the com-
plexity and robustness of the system decreases when glucose con-
centration increases. In our model LZ complexity is thought to be a
measure of the different patterns arising in a process, and therefore
its increase correlates with the number of configurations the system
acquires. This capability is usually deemed to characterize self-
organizing systems and it is associated with increased robustness,
i.e., resilience with respect to stressing events.
Contrary to what has been observed for LZ complexity, we
obtain an increase in entropy production rate associated with
increasing glucose concentration, which coincides with results
obtained from experimental data of HeLa for different growth
conditions [141]. Similar behavior is observed for Pi. Calculations
of entropy rate production for different values of the control para-
meters show that ∂
S_i
∂Pi> 0 and∂S_i
∂Glu> 0.
We believe that such conundrum lies its roots in the divergent
grasping of the entropy production principle [162]. As we have
shown in previous works [14, 81, 82] that if the entropy produc-
tion rate is not used as an extremal principle [163], we should
postulate that those reactions that exhibit a higher value of S_i
necessarily are fundamentals in the process [81]. This statementFig. 15Limit Cycle observed for Glucose 5 mM and Inorganic Phosphate 0.5 mM162 Sheyla Montero et al.