Astressin acetate is an antagonist of corticotropin releasing factor (CRF) with low affinity for the CRF binding protein and high affinity for the cloned pituitary receptor(Ki = 2 nM).

Astressin acetate exhibits high affinity for cloned human CRF-RA1 stably expressed in CHO cells and high potency to inhibit ACTH secretion[2].

Astressin acetate (i.c.v. 30 min before and 10 min after seizures) decreases damage in some hippocampal cell fields by as much as 84%. Astressin acetate protects even if administered only 10 min following excitotoxin exposure[1]. Astressin acetate is significantly more potent than any previously tested antagonist in reducing hypophyseal corticotropin secretion in stressed or adrenalectomized rats. Astressin acetate (30 and 100 μg/kg; i.v.) produces a significant decrease in ACTH levels at 45 and 90 min, respectively[2]. Astressin acetate significantly reverses the anxiogenic-like response induced by both social stress and i.c.v. rat/humanCRF (r/hCRF) on the elevated plus-maze, but fails to block the effects of r/hCRF-induced locomotor activity in a familiar environment[3].