“…However, it is not certain whether there is also a feedback inhibition of CCK secretion; in the rat (Green & Lyman, 1972), and possibly in the chicken (Niess, Ivy & Nesheim, 1972), trypsin in the duodenum inhibits the release of CCK, but this seems not to occur in the dog (Cooke, Nahrwold & Grossman, 1967).…”