Effect of short-term administration of dexamethasone on canine antral gastrin gene expression

The acute effect of corticosteroids on the release and biosynthesis of gastrin still remains unclear. We report the effect of short-term administration of dexamethasone on the antral gastrin gene expression and gastrin levels in 6 dogs, which were treated with dexamethasone (1.5 mg/kg, i.m. daily) for 3 days. One day after treatment, gastrin mRNA levels increased (152 +/- 14%), but serum and tissue gastrin showed no significant changes. With 2 and 3 days of dexamethasone treatment, gastrin mRNA (2 days: 163 +/- 28%, 3 days: 170 +/- 22%), serum gastrin (2 days: from 94 +/- 12 to 168 +/- 23 pg/ml, 3 days: to 180 +/- 16 pg/ml) and tissue gastrin concentration (2 days: from 480 +/- 32 to 664 +/- 31 pg/mg tissue protein, 3 days: to 708 +/- 45 pg/mg tissue protein) significantly increased. However, gastrin mRNA levels were not increased even after 1 day culture of canine antral tissue with dexamethasone in vitro. These findings suggest that short-term administration of corticosteroid may increase the canine gastrin gene expression in vivo by an unknown pathway.