Expression and Distribution of Somatostatin Receptor Subtypes in the Pancreatic Islets of Mice and Rats

• Published in: The journal of histochemistry and cytochemistry 2004-03, Vol.52 (3), p.391-400
• Main Authors: Ludvigsen, Eva, Olsson, Richard, Stridsberg, Mats, Janson, Eva T, Sandler, Stellan
• Format: Article
• Language: English
• Subjects: Animals; Fluorescent Antibody Technique; Islets of Langerhans - cytology; Islets of Langerhans - metabolism; Male; Mice; Mice, Inbred C57BL; Rats; Rats, Sprague-Dawley; Receptors, Somatostatin - biosynthesis; Receptors, Somatostatin - metabolism; Species Specificity
• ISSN: 0022-1554; 1551-5044
• DOI: 10.1177/002215540405200310

Somatostatin acts on specific membrane receptors (sst1–5) to inhibit exocrine and endocrine functions. The aim was to investigate the distribution of sst1–5 in pancreatic islet cells in normal mice and rats. Pancreatic samples from five adult C57BL/6 mice and Sprague-Dawley rats were stained with antibodies against sst1–5 and insulin, glucagon, somatostatin, or pancreatic polypeptide (PP). A quantitative analysis of the co-localization was performed. All ssts were expressed in the pancreatic islets and co-localized on islet cells to various extents. A majority of the β-cells expressed sst1–2 and sst5 in mouse islets, while ≤50% in the rat expressed sst1–5. The expression of sst1–5 on α-cells did not differ much among species, with sst2 and sst5 being highly expressed. About 70% of the 8-cells expressed sst1–4 in the rat pancreas, whereas 50% of the islet cells expressed sst1–5 in the mouse. Furthermore, 60% of the PP-cells expressed sst1–5 in the mouse, while the rat islets had lower values. Co-expression with the four major islet hormones varies among species and sst subtypes. These similarities and differences are interesting and need further evaluation to elucidate their physiological role in islets.