Fig. 2: C3G stimulated GLP-1 secretion in STC-1 cells to indirectly increase insulin release in NIT-1 cells.

A GLP-1 content from culture medium after 24 h STC-1 and NIT-1 co-culture in the presence of C3G (n = 3). B Insulin content from culture medium after 24 h STC-1 and NIT-1 co-culture in the presence of C3G (n = 3). C The GLP-1 content from the culture medium after treating STC-1 cells with C3G alone for 24 h (n = 4). D The insulin content from the culture medium after treating NIT-1 cells with C3G alone for 24 h (n = 4). E Schematic diagram of steps for cell co-culture. F The schematic diagram of C3G stimulates GLP-1 release from STC-1 cells to achieve increased insulin release in NIT-1 cells indirectly. Con-1: negative control under low glucose; Con-2: positive control under high glucose; C3G: 80 μg/mL C3G intervention under high glucose. Any two groups labeled with different letters (e.g., a, b, or c) on the histogram, indicate statistically significant differences (p < 0.05).