Cholecystokinin-like peptides in brain and intestine of obese-hyperglycaemic mice.

Cholecystokinin-(CCK) like peptides have been measured in the brain and small intestine of ob/ob hyperglycaemic mice and lean littermates. CCK-like peptides were measured by radioimmunoassay employing an antiserum to CCK octapeptide (CCK 8) and gastrin 17 I125 label. Although this antiserum detects gastrin with equal affinity to CCK, concomitant assay of tissue extracts with a gastrin specific antibody failed to reveal any detectable gastrin. Extracts of brain and small intestine showed levels of CCK of 96 +/- 12.6 pmol g-1 and 45 +/- 6.1 pmol g-1 in the obese mice; 101 +/- 8.7 pmol g-1 and 36 +/- 2.5 pmol g-1 in the lean mice. These were not significantly different. It has been suggested that CCK may be a satiety factor and it has been reported that there is less CCK in brain of obese mice compared with lean mice. This study has failed to confirm the previous finding and indicates that, in this animal model, tissue levels of CCK probably do not modulate appetite.