Hydrocortisone and 1,25(OH)2D3: role in proliferative responses of the embryonic chick duodenum in organ culture.

The present studies were conducted to determine if hydrocortisone (HC) and/or 1,25-dihydroxycholecalciferol (1,25(OH)2D3) alter proliferative responses of the cultured duodenum, and if such alterations could be related to the known augmentation of 1,25(OH)2D3-induction of a specific, intestinal calcium-binding protein (CaBP) by glucocorticoids. HC stimulated proliferation in the duodenal epithelium, as indicated by increased DNA synthesis (3H-thymidine uptake), increased cell number/villus, and increased mitotic index after colchicine treatment. Goblet cell numbers were not significantly increased with any hormone treatment. The presence of 1,25(OH)2D3 alone did not affect proliferative responses. CaBP concentration as a function of tissue weight was 50% greater in HC stimulated intestine, indicating that the proliferogenic action of HC on the duodenum alone could not account for the glucocorticoid-1,25(OH)2D3 interaction in CaBP synthesis.