Intraventricular CCK inhibits food intake and gastric emptying in baboons
To evaluate the role of cholecystokinin (CCK) as a physiological regulator of meal size and gastric emptying in the baboon, we measured plasma CCK bioactivity during 30-min meals alone and after intravenous or intraventricular infusions of CCK COOH-terminal octapeptide (CCK-8). Both intravenous (2 μg/kg) and intraventricular (1 μg/kg) CCK-8 administration resulted in plasma CCK elevations comparable with normal prandial CCK levels: peak plasma levels were 4.1 ± 0.9, 7.1 ± 1.1, and 4.9 ± 2.2 pM for pooled intravenous and intraventricular control, intravenous, and intraventricular conditions. Also, both treatments appeared to reduce gastric emptying as indicated by a significant suppression of postprandial plasma insulin and glucose levels. However, only intravenous CCK reliably reduced meal size (percent of control meal size was 91 ± 5% or 43 ± 19% with intravenous or intraventricular CCK). We conclude that circulating endogenous CCK is a potent postprandial endocrine regulator of gastric emptying. However, the ability of CCK to decrease meal size may require direct interaction with the central nervous system.
Figlewicz, DP; Sipols, AJ; Porte, D; Woods, SC; Liddle, RA
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