Ghrelin- and growth hormone secretagogue receptor-immunoreactive cells in Xenopus pancreas

Ghrelin and its receptor, growth hormone secretagogue receptor (GHS-R), are produced by various cell types and affect feeding behavior, metabolic regulation, and energy balance. In the mammalian pancreas, the types of endocrine cells immunoreactive for ghrelin vary. Further, no study has clarified the type of endocrine cells producing ghrelin and GHS-R in the non-mammalian pancreas. We immunohistochemically investigated ghrelin-like and GHS-R-like immunoreactivities in the Xenopus pancreas. Ghrelin-immunoreactive cells were observed both in islets and extrainsular regions, and they corresponded to insulin-containing cells. GHS-R-immunoreactive cells were observed in the islets, and these immunoreactive cells corresponded to insulin- and somatostatin-containing cells. These observations suggest that ghrelin is co-secreted with insulin and that ghrelin may act in an autocrine fashion for insulin-containing cells and in a paracrine fashion for somatostatin-containing cells in this species. (C) 2011 Elsevier B.V. All rights reserved.