Role of thyroxine and insulin on the development of the fetal mouse duodenum in organ culture.
The role of thyroxine and insulin in the regulation of proliferation and differentiation of the immature duodenal epithelium of the fetal mouse was investigated using an organ culture method with a serum-free medium. Thyroxine (10 nM) stimulates specifically the activity of maltase. Insulin (125 mU/mL) remains without effect on the maturation of all hydrolytic functions studied. Each hormone significantly increases the percentages of brush border enzyme activities liberated in the medium and reduces the amount of glucose released in the medium. In the presence of dexamethasone (76 nM) the effect of thyroxine on maltase activity is still observed. Finally, thyroxine and insulin do not modify the labelling index in the duodenal crypts of the explants in the presence or absence of dexamethasone. These findings indicate that thyroxine and insulin can act directly on the development of the fetal mouse duodenum at the end of gestation. Nevertheless, their implication in prenatal development of the gut functions appears to be of minor importance.
D000818:Animals; D001345:Autoradiography; D002454:Cell Differentiation; D003907:Dexamethasone / Q000494:pharmacology; D004386:Duodenum / Q000196:embryology* / Q000201:enzymology; D005947:Glucose / Q000378:metabolism; D007328:Insulin / Q000502:physiology*; D007413:Intestinal Mucosa / Q000196:embryology; D051379:Mice; D008813:Mice, Inbred ICR; D008871:Microvilli / Q000201:enzymology; D009924:Organ Culture Techniques; D013974:Thyroxine / Q000502:physiology*
D007328:Insulin; D003907:Dexamethasone; D005947:Glucose; D013974:Thyroxine