THE RELEASE OF CORTICOTROPHIN BY ANTERIOR PITUITARY TISSUE IN VITRO

Abstract

The release of ACTH by rat anterior pituitary tissue in vitro was used as a test system for the detection of factors that stimulate ACTH-release. The results indicate that:1. Epinephrine or arterenol, added by themselves, are without effect.2. Hypothalamic tissue alone is also ineffective.3. The combination of hypothalamic tissue with epinephrine or arterenol increases the release of ACTH about threefold.4. Brain cortex can replace hypothalamus.5. Liver cannot replace neural tissue; acetyl choline and serotonin cannot replace epinephrine or arterenol.6. The greatest stimulation of ACTH-release (six- to eight-fold) occurs with posterior pituitary tissue plus arterenol. The arterenol may be replaced by hypothalamus or sphingosine, but not by dopamine (3,4-dihydroxyphenylethylamine), which is structurally similar to arterenol.7. The posterior pituitary is probably involved in the response of the anterior pituitary–adrenocortical system to stress.