A computer model of pancreatic islet glycolysis.

We have modeled an experiment with perifused pancreatic islet cells using our BIOSSIM language. The experiment and the resulting model are concerned with glucose uptake and glycolysis by the beta-cells of pancreatic islets. Although glycolysis appears to be involved in insulin release, we do not have enough information to represent insulin release in detail.

Pancreatic islet discrimination of hexose anomers. II. Transient computer simulation.

We have previously modeled pancreatic islet glycolysis under idealized steady-state conditions where the input is a pure hexose anomer and there is no mutarotation and reproduced the known preference for the alpha-anomers of glucose and mannose as substrates. This model is here extended to simulate real experiments, where the hexoses mutarotate and measurements may be taken over time. The behavior of our model system agrees with available experimental data.

Pancreatic islet discrimination of hexose anomers. I. Steady-state computer simulation.

Pancreatic islets detect glucose level by phosphorylating it and converting the glycolytic rate to a signal to secrete insulin. Insulin secretion is greater from the alpha- than from the beta-anomer when the D-glucose level is below 22 mM. D-mannose behaves similarly but at nearly twofold higher concentrations.

Modeling and artificial intelligence approaches to enzyme systems.

Modeling is a means of formulating and testing complex hypotheses. Useful modeling is now possible with biological laboratory microcomputers with which experimenters feel comfortable. Artificial intelligence (AI) is sufficiently similar to modeling that AI techniques, now becoming usable on microcomputers, are applicable to modeling.

Computer simulation of metabolism of glucose-perfused rat heart in a work-jump.

A computer model of glycolysis, the tricarboxylic acid cycle, and related amino acid metabolism, is described for a glucose-perfused experimental rat heart preparation suddenly switched from low work load (Langendorff perfusion) to high work load (left atrial perfusion). Glycolytic intermediate measurements suggest activation of phosphofructokinase within a few seconds. This activation, and also that of other glycolytic enzymes, is calculated as due to a sharp increase in cytoplasmic Mg2+ level, which overcomes the inhibitory effects of a rapid fall in cytoplasmic pH to 6.