Extrahypothalamic distribution of CRF-like immunoreactivity in the rat brain

CRF-like immunoreactivity was measured by radioimmunoassay in the brains of normal adult rats and found to be widely distributed in extrahypothalamic areas (e.g., thalamus, amygdala, hippocampus, frontal cerbral cortex, striatum, midbrain, pons-medulla and cerebellum) at levels approximately 10% of the hypothalamus. Sephadex G-50 gel filtration reveals that CRF-like immunoreactivity in the hypothalamus coelutes with synthetic ovine CRF and is also present in the void volume. However, in the extrahypothalamic areas of the rat brain, only CRF-like immunoreactivity that coelutes with synthetic ovine CRF was detected. High performance liquid chromatography revealed equal amounts of immunoreactivity coeluting with CRF and methionine sulfoxide CRF in hypothalamic extracts.