Pituitary-Adrenal Influences on Fear Responding

Science  10 Jan 1969:
Vol. 163, Issue 3863, pp. 197-199
DOI: 10.1126/science.163.3863.197


In a passive avoidance situation, hypophysectomized male rats show less fear than normal rats, whereas adrenalectomized rats show greater fear than normals. These results probably occur because hypophysectomized rats lack adrenocorticotrophic hormone, which increases arousal or emotionality, whereas adrenalectomized animals lack certain adrenal steroids, which inhibit excitatory effects. The results indicate that adrenocorticotrophic hormone and certain adrenal steroids have opposite effects in regulating fear-motivated behavior.