Fig. 2

Construction, paramaterisation and hypothesis testing using a cell-specific model of rat Leydig cell steroidogenesis. a An image of the editable framework of rat Leydig cell steroidogenesis, with parameterisation details. The black bar graphs next to each enzyme input show the number of tokens added to each enzyme node at the three stages of progenitor, immature and adult Leydig cell. The tokens are introduced to the node by editing the properties of the arrow leading from the token input to the node, and are visible as a numerical string next to the node. Androstenedione is indicated by a green ring, testosterone in blue and 3α-diol in red. b Still frames from the dynamic signalling Petri net outputs of the Leydig cell model at the three stages of progenitor, immature and adult. Each of the coloured shapes on the diagram represents a steroid node in the same position as the yED diagram above. Larger red shapes indicate more tokens are flowing through that node, smaller blue shapes indicate fewer and no shape indicates no tokens. c A graph visualising the flow of tokens through the nodes representing testosterone (blue) and 3α-diol (red) over the course of Leydig cell maturation. The coloured areas around the line indicate the variance of the output