ARTERIAL OXYGEN PARTIAL PRESSURES REDUCE THE INSULIN-DEPENDENT INDUCTION OF THE PERIVENOUSLY LOCATED GLUCOKINASE IN RAT HEPATOCYTE CULTURES- MIMICRY OF ARTERIAL OXYGEN PRESSURES BY H2O2

Liver glucokinase (GK) is localized predominantly in the perivenous zo ne. GK mRNA was induced by insulin maximally under venous O-2 partial pressure (pO(2)) and only half-maximally under arterial pO(2). CoCl2 a nd desferrioxamine mimicked venous pO(2) and enhanced the insulin-depe ndent induction of GK mRNA under arterial pO(2). H2O2 mimicked arteria l pO(2) and reduced insulin-induced GK mRNA under venous pO(2) to the lower arterial levels. Thus the zonal O-2 gradient in liver seems to h ave a key role in the heterogenous expression of the GK gene.