Distribution of ghrelin-producing cells in stomach and the effects of ghrelin administration in the house musk shrew (Suncus murinus).

OBJECTIVE: To investigate the distribution of ghrelin, an important appetite regulatory factor related to obesity, in the stomach of Suncus murinus, and attempted to elucidate the ghrelin-mediated regulatory effect in this animal.

METHODS: The stomachs of Suncus murinus were divided into 5 sections, cardia, fundus, greater curvature, lesser curvature, and pylorus, for investigating the ghrelin-producing cells by immunohistochemistry and Western blotting. Then Suncus murinus were randomized into two groups with ghrelin intraperitoneal injection (ghrelin-ip group) and saline intraperitoneal injection (control group), respectively. The effects of food intake and body weight were measured, and furthermore, the distribution of ghrelin in stomach was also investigated by immunohistochemistry and Western blotting.

RESULTS: The immunolocalization and protein levels of ghrelin differed significantly in different regions of the stomach of Suncus murinus. Furthermore, ghrelin administration did not change the rate of food intake, but resulted in an increase in body weight compared with the control group. In this study, we elucidated the distribution of ghrelin-producing cells in the stomach of Suncus murinus in detail for the first time. Ghrelin intraperitoneal administration was found to induce an increase in body weight without changing food intake in this species.

CONCLUSION: Our study implied ghrelin showed a different regulatory function in Suncus murinus from other species. It is considered that ghrelin may be associated with obesity-resistance phenomenon in Suncus murinus.