GCG and diabetes mellitus: To more fully explore the connection between lysosomal trafficking and glucagon hypersecretion in diabetes, we hypothesized that glucagon may be secreted through Lamp1+ lysosomes, which have been implicated in the secretion of lysosomal cargo.26 We therefore immunostained αTC1-6 cells for the lysosomal transmembrane protein, Lamp1, together with Stmn2and glucagon (Figure 7B).