The Validity of Using Plasma Corticosterone as a Measure of Stress in the Turkey. ∗ † ‡

Summary

Corticosterone was established as the principal free corticosteroid found in turkey plasma. A routine procedure based on the fluorescence of corticosterone was used for quantitation of free corticosterone in peripheral plasma of the turkey. Using this technic it was demonstrated that exogenous ACTH injected intramuscularly significantly increases the level of free corticosterone in peripheral plasma. Likewise, it was shown that the stressors of water deprivation and cold significantly elevate plasma corticosterone and that hypophysectomy abolishes this latter effect. It is suggested that these data indicate the validity of using plasma corticosterone concentration as a measure of severity of stress conditions in the birds. These data also support the postulate that the bird adrenal may be relatively autonomous and, therefore, functions at a relatively high level in the absence of anterior pituitary function.