The dependence of duodenal differentiation in chick embryos on pars distalis hormones

摘要: Duodenal differentiation in normal chick embryos between 15·75 and 20·5 days of incubation was characterized by the following changes: 1. The dry weight increases from 4·1 to 12·4 mg. 2. alkaline phosphatase activity less than 12 426 units. 3. length villi sixfold. 4. height epithelial cells at villous tips 12·9 25·9 μ. 5. shape mucosal changes low columnar, cuboidal, high columnar. 6. nuclei progresses round ovoid. 7. At first mitotic figures are distributed throughout epithelium but become restricted crypts Lieberkuhn. 8. Cytoplasmic glycogen appears day is mobilized days. 9. A mucopolysaccharide brush border progressively 16·75 amount. 10. Alkaline (Gomori technique) levels becomes more intense. 11. Fresh body weights third toe lengths 19·75 were recorded as indices growth. In ‘hypophysectomized’ 19·75–21·5 age: 12. level duodenal approximated that 16·75–17·75 embryos. 13. ‘phypophysectomized’ which received a pars distalis chorioallantoic homograft 9·5 duodena normal. 14. with grafts became atrophic not different untreated 15. depends on hormones.