Abstract
We demonstrate that formal neural network techniques allow us to build the simplest models compatible with a limited but systematic set of experimental data. The experimental system under study is the growth of mouse macrophage like cell lines under the combined influence of two ion channels, the growth factor receptor and adenylate cyclase. We conclude that three components out of four can be described by linear multithreshold automata. The remaining component behaviour being non-monotonic necessitates the introduction of a fifth hidden variable, or of nonlinear interactions.