A comparison of hepatic glucokinase gene expression in high- and low-activity strains of mice

1. Compared with the rat, mouse liver glucokinase activities show a different sensitivity to changes in insulin concentrations. When animals from a high glucokinase-high insulin level strain C3H/He are crossed with those from a low glucokinase-low insulin strain C58, individuals from recombinant inbred lines show non-parental phenotypes with high glucokinase activity but low insulin and vice versa. 2. Messenger RNA levels are greater in high-enzyme-activity mice strains than in low-activity animals, suggesting that differences in either transcription of the glucokinase gene or in mRNA stability occur between the two strains. 3. There is no evidence of a different number of glucokinase genes in the high- and low-activity strains. Differences in activity therefore suggest that dissimilarities in the regulation of the expression of these genes may well occur.