Oscillations in activities of enzymes in pancreatic islet subcellular fractions induced by physiological concentrations of effectors.

Glucose, the most potent insulin secretagogue, stimulates insulin secretion by aerobic glycolysis, but other secretagogues stimulate insulin release exclusively by mitochondrial metabolism. It is well known that in the intact pancreatic beta-cell, either kind of secretagogue can induce oscillations in metabolism (e.g.

Cell swelling and glycogen metabolism in hepatocytes from fasted rats.

Cell swelling is known to increase net glycogen production from glucose in hepatocytes from fasted rats by activating glycogen synthase. Since both active glycogen synthase and phosphorylase are present in hepatocytes, suppression of flux through phosphorylase may also contribute to the net increase in glycogen synthesis by cell swelling. We have developed an isotopic procedure to estimate the fluxes through glycogen synthase and phosphorylase in intact hepatocytes and we have examined the effect of cell swelling on both enzyme fluxes.

Relationships between age-dependent changes in the effect of almitrine on H(+)-ATPase/ATPsynthase and the pattern of membrane fatty acid composition.

The effects of almitrine on ATPase/ATPsynthase previously described in beef heart mitochondria (Rigoulet et al. (1990) Biochim. Biophys.