GLP-1R cellular association in gastric principal glands of PO and SPD rats. Longitudinal sections of gastric principal glands of PO (a, b, c) and SD rats (d, e, f). H&E staining (left panels) and GLP-1R immunostaining (right panels) are shown (magnification ×40). (a, d) Neck area of principal glands of PO (a) and SPD (d) rats is dominated by acid secreting parietal cells (solid arrows) which display strong GLP-1R immunoreactivity. Mucous secreting neck cells (broken arrows) demonstrate no GLP-1R immunoreactivity. (b, e) Mid area of principal glands of PO (b) and SPD (e) rats is populated by acid secreting GLP-1R immunostained parietal cells (solid arrows) and chief cells without GLP-1R immunoreactivity (square head arrows). (c, f) Bottom area of principal glands of PO (c) and SPD (f) rats. GLP-1R immunopositive enteroendocrine-like cells (head only arrows), parietal cells (solid arrows), and chief cells (square head arrows) without GLP-1R immunoreactivity are shown. Bar = 20 μm.