Activation of hepatic and inactivation of renal xanthine dehydrogenase activity by dexamethasone during the prenatal period in chick eggs.

In the experiments reported here, the effect of dexamethasone on hepatic and renal xanthine dehydrogenase toward the end of incubation was studied. Dexamethasone injected on day 17 of incubation into the chick eggs increased the hepatic and decreased the renal activity of xanthine dehydrogenase. Furthermore, dexamethasone was found to accelerate fetal development as measured by the precocious decrease of thymidine uptake into nuclear DNA and by the increased fetus weight/egg weight ratio. The data suggest that an activation of xanthine dehydrogenase is caused by a hatching-independent factor and by a factor related to the hatching process.