Pork Peptone Stimulates Cholecystokinin Secretion from Enteroendocrine Cells and Suppresses Appetite in Rats

Soybean β-Conglycinin Bromelain Hydrolysate Stimulates Cholecystokinin Secretion by Enteroendocrine STC-1 Cells to Suppress the Appetite of Rats under Meal-Feeding Conditions

“…This result shows BconB to be a potent appetite suppressor via CCK release from EECs and also suggests the direct acceptance of these peptides by CCK-producing I-cells in the small intestine as those peptides already shown in previous studies. [9][10][11]14,15) Although the in vivo study gives no evidence for the suppression of appetite by BconB being CCK-dependent, the strong ability of BconB for CCK release from EECs in vitro suggests that BconB-induced appetite suppression was dependent on CCK secretion. We did not measure the release of CCK in vivo, so there is also a possibility that the BconBinduced appetite suppression was associated with the The rats (14-week-old male Sprague-Dawley animals weighing about 400 g) assigned to 3 groups (water, n ¼ 6), (BconB50, n ¼ 5) and (BconB200, n ¼ 5) were preloaded with either the active CCK-releasing and appetite-suppressing peptide, BconB, as 50 and 200 mg/1 mL of distilled water or with only water as a negative control.…”

“…This raises the possibility of the peptides in BconB screened in vitro being resistant to luminal events or at least retaining the active structure for a CCK-stimulating response in vivo to induce appetite suppression, as has been shown for BconP in early studies. 10,11,14) BconB was further examined for its appetite-inhibiting effects on rats under meal-feeding conditions; we found that BconB50 reduced the evening food intake, but failed to decrease the morning intake ( Fig. 5A and B).…”

“…The possibility of the synergistic release of gut satiating hormones in response to peptide-induced CCK secretion has already been suggested in an earlier report. 14) Indeed, there are limitations to quantifying plasma CCK due to the active sequence homology and cross-reactivity between CCK and another gut hormone, gastrin. 21,22) Rat mucosal tissue in the intestine also does not solely consist of I-cells, resulting in a tedious process for isolation.…”

“…[9][10][11][12][13] These findings were further supported by the result that peptones stimulated CCK secretion in CCK-producing murine enteroendocrine STC-1 cell line. [14][15][16][17][18] We have previously demonstrated that an intraduodenal infusion of peptides from a peptic hydrolysate (peptone) of soybean -conglycinin suppressed the food intake by duodenally-cannulated rats and directly stimulated CCK release from the EECs. 10,11) We later showed that an orogastric administration of pork peptone under more physiological conditions suppressed the appetite of rats by the release of CCK from the EECs.…”

“…10,11) We later showed that an orogastric administration of pork peptone under more physiological conditions suppressed the appetite of rats by the release of CCK from the EECs. 14) We have previously found several CCK-releasing and appetite-suppressing peptic digests from various protein sources, [9][10][11]14,15) although the effect of hydrolysates obtained by proteases other than pepsin on CCK release and appetite suppression have not been studied. Furthermore, the bitter oro-sensory characteristic of peptic hydrolysates appeared to be less suitable for oral consumption in human applications.…”