Rat Hypothalamic Corticotropin-Releasing Factor (CRF) Content Remains Constant Despite Marked Acute or Chronic Changes in ACTH Secretion

Abstract

Hypothalamic corticotropin-releasing factor (CRF) activity was only slightly increased by 1 min ether stress and was unaltered by 2.5–10 min ether stress, 15-day adrenalectomy, 11-day hypophysectomy or 3-day dexamethasone treatment. There was a slight tendency for the hypothalamic CRF activity to be higher in the p.m. than in the a.m. Basal hypothalamic deafferentation did not significantly affect hypothalamic CRF content in the a.m. or p.m. compared to intact controls. We conclude that hypothalamic CRF content maintains relative constancy under conditions of marked acute or chronic stimulation or suppression of ACTH secretion.