Trypsin inhibitor and maternal reunion increase plasma cholecystokinin in neonatal rats

Abstract Intragastric soybean trypsin inhibitor increased plasma CCK bioactivity by 87% in nondeprived, 9–12-day-old rat pups. Reunion with the dam for 1 h after overnight maternal deprivation also increased plasma CCK significantly. These results demonstrate that CCK can be released from the small intestine of rats as early as postnatal day 9.