Hypoxia, or a low concentration of oxygen, is encountered in humans undertaking activities such as mountain climbing and scuba diving. Although data on the interplay between hypoxia and gastrins are limited, circulating gastrin concentrations rise in rats and newborn calves exposed to experimental hypoxia, and in humans exposed to high altitude. Gastrin expression is upregulated by hypoxia in gastrointestinal cell lines [1], and gastrins have been shown to stimulate angiogenesis in vitro and in vivo [2]. Aim: The aim of this study was to determine if higher gastrin concentrations were protective against hypoxia.Methods: Mice (8-10 weeks old) over-expressing gastrin (hGAS) and mice of the corresponding wild-type strain (FVB/N) were subjected to normoxia (21% oxygen; air) or hypoxia (10% oxygen) for 10 days in an enclosed normobaric chamber. Mice were weighed daily and sacrificed on day 10 by inhalational overdose with the anaesthetic isoflurane, and blood and tissues were collected for further analyses.Results: hGAS mice lost significantly less weight (<10%) than FVB/N mice (>15%) exposed to hypoxia, compared to their normoxic counterparts. hGAS mice also had significantly better health scores than FVB/N mice under hypoxia. Although hypoxic FVB/N mice had a decreased spleen weight and a reduced number of platelets compared to normoxic FVB/N mice, no difference in spleen weight was observed in hGAS mice under hypoxia or normoxia.Conclusion: The observation that higher concentrations of gastrins decreased the amount of weight loss in animals exposed to hypoxia provides evidence that gastrins may play a protective role in low oxygen conditions.