RÉSUMÉ
Shay rats and conscious rabbits were used to study the effect of sex hormones on gastric secretion. Daily injections of estradiol-di propionate and testosterone-propionate were given separately to each set of animals, while the control animals received solvent alone for the same duration of time. Estrogen inhibited gastric acid output but augmented the mucus secretion as evidenced by increased hexosamine and fucose contents; and testosterone had the reverse effects. The effect of estrogen was more potent that of testosterone. An inverse relationship between gastric acid and mucus secretion has been noted. Peptic activity varied independently of the acid output. These hormones seemed to vary the acid output by modifying the composition of mucus secretion.