The results showed that at high altitude there is a diminished acid secretion to histamine stimulation, which might be related to a lower sensitivity of parietal cells produced by hypoxia. The hypergastrinemia might reflect a compensatory higher G cells activity in order to maintain an adequate gastric function both at basal state and after food intake.
Jó, N., García, O., Jara, R., Garmendia, F., Nago, A., García, R., Hidalgo, H., & Flores, L. (1987). Serum gastrin and gastric acid secretion at high altitude. Hormone and Metabolic Research, 182-183. https://doi.org/10.1055/s-2007-1011772