Immunological evidence of cholecystokinin-39 in porcine brain.

Using a sensitive and specific radioimmunoassay for cholecystokinin-39 (CCK-39), CCK-39 was demonstrated in aqueous-acid extracts of procine brain. The highest concentration of CCK-39 was found in the cortex (6.1 +/- 1.5 pmol/g). In the cortex CCK-39 comprised 21% of total CCK-immunoreactivity and 51% of large CCK-immunoreactivity.