Figure 1.

The direct physiologic effects of endogenous glucagon-like peptide-1 (GLP-1; black arrows), glucose-dependent insulinotropic polypeptide (GIP; green arrows), glucagon (red arrows), and amylin (blue arrows). The corresponding representation of these four peptides in target tissues is denoted by a black asterisk, green triangle, red rectangle, and blue circle, respectively. These four peptides exert their effects on the hypothalamus, either directly or indirectly through neuronal conduction, ultimately leading to a reduction in food intake. Adapted from Kim.³³ AP, area postrema; NTS, nucleaus tractus solitarius; BAT, brown adipose tissue; WAT, white adipose tissue.