| The hypothesis of this study was that digestion of proteins gives rise to peptides that initiate several satiety signals from gut, and that signals arising will be dependent on protein source. The role of peripheral opioid and CCK-A receptors was investigated. Casein, soy and their hydrolysates were administered to rats by gavage. Food intake was measured over 2 hours. The opioid receptor antagonist, naloxone methiodide, increased food intake when given at the same time as hydrolysate preloads, 25 minutes after casein preloads and 55 minutes after soy preloads. The CCK-A receptor antagonist, devazepide, given 60 minutes before three soy hydrolysates, also blocked suppression of food intake, but the strength and duration of the interaction varied with preparation. When both receptor antagonists were given with preloads, their effects were additive. It is concluded that peptides arising from digestion contribute to satiety by independent activation of both opioid and CCK-A receptors. |
