Figure 4. Negative feedback in response to an injection of dexamethasone (DEX) (a) and maximum corticosterone (CORT) secretion in response to an injection of adrenocorticotropin hormone (b) in house sparrows after four weeks of exposure to a 1% oil or a control diet (n = 12 birds in each group).

The star represents a significant decrease in adrenal sensitivity in birds on the oil diet compared to controls. Values are presented as mean ± SEM.