The effects of hydrocortisone and thyroxine treatments on development of duodenal morphology, alkaline phosphatase, and sugar transport in chicken (Gallus gallus) embryos

The ability of thyroxine (T4) and hydrocortisone (H), alone or together, to cause precocious duodenal development was tested in chicken embryos. Correlations in the levels of duodenal enzymic, structural, and absorptive properties were compared in intact and treated embryos. Duodenal alkaline phosphatase activity, morphogenesis, and sugar absorption develop together in untreated embryos. Precocious alkaline phosphatase activity, morphogenesis, and α-methylglucoside uptake were correlated after H and T4 treatments. These parameters also responded significantly to T4 treatments alone. The levels of the alkaline phosphatase activity in 16.5-day embryos were three times normal after H plus T4 treatment. No parameters changed significantly after H treatment alone. Parallel increases in alkaline phosphatase activity and morphogenesis probably reflect duodenal participation in sugar uptake functions, at least for duodenal maintenance. Adrenocorticoids and thyroid hormones could be involved in these aspects of normal duodenal development.