Use of glucose analogues to study the mechanism of glucose-mediated cAMP increase in yeast

The addition of glucose to yeast triggers a transient, several-fold increase in cAMP levels followed by a permanent 2-fold increase. The transient increase can be provoked by a variety of glucose analogues, even those that cannot be phosphorylated, and also by galactose. The extent of the increase appears to be correlated with the affinity of the transport system for the different sugars. The permanent increase in cAMP occurs only with sugars that can be efficiently phosphorylated. The maximal cAMP concentration reached after addition of the sugars determines the extent of inactivation of fructose-1,6-bisphosphatase.This work was sup- ported in part by a grant of the CAICYT