FIGURE 1.

GLP-1 release in response to phenylalanine and accumulative calcium perfusion. Rat small intestine was perfused with Krebs–Henseleit buffer deplete of calcium ± 10 mM phenylalanine. At 20 min, Ca²⁺ was reintroduced cumulatively into the perfusate every 15 min over 90 min. The figure depicts the extracellular Ca²⁺–GLP-1 response relation using AUC for each Ca²⁺ addition. Student unpaired t tests were used to determine significance between control and phenylalanine: **P < 0.01, ***P < 0.001. GLP-1, glucagon-like peptide 1. Reproduced from reference 34 with permission.