Distribution of corticotropin releasing factor(s) activity in neural and extraneural tissues of the rat.

Distribution and dose-response characteristics of corticotropin releasing factor(s) (CRF) activity in the central nervous and extraneural tissues of the rat were examined with a sensitive CRF bioassay using ACTH secretion by cultured rat adenohypophyseal cells. Dose-response curves for hypothalamus were steeper than and not parallel to those for cerebral cortex, liver, serum or human urine. The minimum effective dose was smallest for the posterior pituitary. CRF activity of the basal hypothalamus was considerably higher than that in other parts of the hypothalamus, and was unaltered by 2.5 or 10 min ether stress. Our data indicate that "specific" CRF is concentrated primarily in the basal hypothalamus and posterior pituitary and is not identical with widely distributed extrahypothalamic extraneurohypophyseal CRF.