Abstract

Background: Proteins are more satiating than fat and carbohydrate but in a sourcedependent manner. Whey Protein Isolate (WPI) and Glycomacropeptide (GMP) suppress Food Intake (FI) in both humans and animals. The objective of this study was to compare the effect of whey protein and GMP preloads on regulation of FI and blood glucose in male Wistar rats. In this study, Rats were allocated to five groups and received one of following in a cross-over design: 1) water; 2) WPI; 3) WPI+devazepide (CCK-1 receptor blocker); 4) GMP; and 5) GMP+devazepide. Food intake, plasma glucose, insulin, CCK and ghrelin were measured.

Results: Plasma CCK concentration was higher 30 min after administration of WPI and GMP compared with the water control. Devazepide increased FI when it was co-administered with WPI and GMP preloads at 1 hour compared with FI after administration of WPI or GMP alone. Ghrelin was lower after WPI administration compared with water control. No differences in glucose and insulin concentrations were observed.

Conclusion: CCK-1 receptors mediate FI suppression induced by both WPI and GMP. However, this effect is limited to the first hour of FI. No differences in the effect of WPI and GMP on glucose metabolism were observed.

Keywords: Whey protein, glycomacropeptide, food intake, CCK-1 receptors, devazepide, wistar rats.

Graphical Abstract