Effects of metyrapone on plasma corticosterone concentration in Gallus domesticus

l. Metyrapone (75 or 150 mg/kg body wt) was injected into fed and starving birds and their plasma corticosterone concentrations monitored.2. Metyrapone stimulated a hypercorticosteronaemia in fed but not in starving birds. It persisted for up to 4 hr. No significant hypocorticosteronaemia was noted subsequently.3. Pretreatment (2 hr) with metyrapone inhibited the response to exogenous ACTH.