The distribution of corticotrophin-releasing factor immunoreactivity in various ovine tissues.

The presence of CRF in various ovine tissues has been quantified by a radioimmunoassay using an antibody raised against ovine CRF synthesized in vitro. Acetic acid extracts of ovine hypothalamus, cerebral cortex, cerebellum, pituitary and a number of visceral organs assayed in serial dilutions gave inhibition curves parallel to those of synthetic CRF. The highest concentration of CRF immunoreactivity (CRF-I) was found in the pituitary (84.6 +/- 8.77 ng/g wet weight) and the second highest in the hypothalamus (79.1 +/- 2.77 ng/g wet weight). CRF-I in the cerebral cortex and visceral organs (stomach, duodenum, jejunum, ileum, pancreas and liver) was about 60 and 30% of that in the hypothalamus, respectively. Chromatography of extracted CRF-I from these tissues on Bio-Gel P-10, equilibrated and eluted with 0.1 M acetic acid, revealed a single immunoreactive peak corresponding to synthetic ovine CRF. These findings indicate that CRF is generally distributed throughout ovine tissues including visceral organs, although its function remains to be clarified.