Growth hormone (GH) gene expression is not confined to the somatotrophs of the pituitary gland and occurs in many extrapituitary tissues, including those of the neural, immune and reproductive systems (Harvey, 2010). Its presence in exocrine glands is, however, largely unknown. The possible presence of GH in salivary glands (the submandibular and parotid glands), in the lachrimal gland and in the exocrine pancreas of rats was therefore investigated by confocal immunocytochemistry. Intense GH-immunoreactivity was demonstrated in the parotid and submandibular glands, particularly in the interlobular and intralobular epithelial ducts and in some (but not all) serous and some mucus acinar cells. The presence of GH immunoreactivity inside the salivary ducts indicates the exocrine secretion of GH into saliva. Within the ductal epithelia of the salivary glands, the GH-immunoreactivity was consistently colocalized with immunoreactivity for mucin-1, salivary amylase, renin and nerve growth factor. It was also colocalized with SMR-1 (submandibular rat-1) in some acinar cells. Similar, but weaker, GH staining was also seen in the lachrimal glands. In the pancreas, some acini were GH-negative and some were GH-positive, whereas intense GH-staining was seen in the intermingled alpha (glucagon-immunoreactive) islet cells, but not in the GH-negative (insulin-immunoreactive) beta cells. The GH-immunoreactivity in these tissues was also colocalized with GH-receptor immunoreactivity, suggesting local (non-endocrine) roles for GH in their exocrine activity. In summary, these novel results demonstrate the presence of GH and its receptor in exocrine tissues of the rat, in which GH may have hitherto unsuspected autocrine, paracrine or lumenocrine roles in salivary, lachrimal or pancreatic exocrine function.