FIGURE 2.

Overview of the hypothesized physiological roles of ghrelin, CCK, GLP-1, and PYY(3–36) in the control of eating and of meal-related glycemia. Gastric emptying, which controls the rate of appearance of ingested food in the small intestine, intestinal transit, rate of digestion, and small intestinal nutrient sensing are the major determinants of the inhibition of ghrelin secretion and the stimulation of CCK, GLP-1, and PYY(3–36) secretion during and after meals. Left: changes in hormone levels lead to GI and central nervous system events whose outcome is to inhibit eating. Right: changes in hormone levels lead GI, pancreatic, hepatic, and central nervous system events whose outcome is to dampen postprandial increases in blood glucose. All four hormones have been hypothesized to contribute to each type of outcome. MS, monosaccharides; FFA, free fatty acids; AA, amino acids.