[CRF-like immunoreactivities in mammalian brains examined with a radioimmunoassay for CRF].
A sensitive and useful radioimmunoassay for CRF was established using synthetic ovine CRF. CRF-like immunoreactivities of hypothalami in the bovine, human, rat, guinea pig, and mouse could be detected with this radioimmunoassay. A variety of CRF-like immunoreactivities of hypothalami in the mammalian brains led us to discuss a putative species difference of amino-acid structure in CRF. In the bovine, CRF-like immunoreactivities of the frontal cortex, caudate nucleus, putamen, and hippocampus could be detected in addition to CRF-like immunoreactivity of hypothalamus. These observations suggested a wide distribution of CRF in the central nervous system, and gave room for discussion about a physiological role of extrahypothalamic CRF. Gel chromatographic studies revealed a high-molecular-weight form of CRF-like immunoreactivity in the bovine frontal cortical profile that was not found in the hypothalamic profile. The results show a multiplicity of CRF-like immunoreactivity in the bovine brain.