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.