The effects of steroids upon the gastrointestinal tract.

The steroid hormones and bile acids are important to digestive tract structure and function. Glucocorticoids administered during pregnancy have been shown to induce cleft palate in the of fspring in several species. Postnatally, a significant rise in corticosterone during week 3 in the rat coincides with profound morphological and biochemical changes in the small intestine toward the adult state. Exogenous glucocorticoids given suckling rats leads to precocious development of these changes. In the adult, glucocorticoids increase brush border enzyme levels, while adrenal insufficiency decreases mucosal weight, enzyme activity, and absorptive functions. Water and sodium absorption and potassium excretion are enhanced in both small and large intestine. The jejunum, through its sense of food, provides the entraining signal that governs corticosterone rhythm. In the stomach, high doses of glucocorticoids inhibit prostaglandin biosynthesis, thereby inhibiting the gastric alkaline response and producing severe g...