CCK

reduces food intake exclusively through actions on vagal afferent fibres

signalling to the NTS, unlike GLP-1 which can act directly on neurons in the

hypothalamus.

CCK

levels peak 6 hours after a meal, whereas PYY and GLP-1 levels peak within 15

minutes.

CCK

crosses the blood-brain barrier directly to act on the PVN, whereas PYY acts

only on the Area Postrema.

CCK

is secreted from L-cells in the rectum, while PYY is secreted from I-cells in

the duodenum.