title: Sequestration of 3H-vitamin D3 by the fetal and neonatal rat liver.
abstract: 19- to 21-day-old fetuses as well as 3-, 7-, 14-, and 22-day-old pups were used to evaluate the sequestration of a tracer dose of 3H-D3 by the fetal and neonatal rat liver. In fetuses, 3H-D3 was injected directly into the umbilical vein; in neonates, 3H-D3 was injected into the portal vein. In both cases, 14C-sucrose was used as extracellular marker. 3H-D3 sequestration was evaluated at 11.3 +/- 1.1% (means +/- SEM) in fetuses, 3.3 +/- 0.6, 4.9 +/- 0.6, 6.3 +/- 0.5 0.5 and 42.0 +/- 1.9% of the dose administered in 3-, 7-, 14-, and 22-day-old rats, respectively. These results clearly show that, in the rat, the fetal liver can take up 3H-D3. Moreover, when compared to the values obtained in the late fetal period, 3H-D3 uptake decreased significantly during the first 2 weeks post partum (p less than 0.0001) and then dramatically increased (6-fold, p less than 0.0001) between days 14 and 22 post partum, when it reached an uptake capacity similar to that previously observed in adult rats.
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D001692:Biological Transport; D002762:Cholecalciferol / Q000378:metabolism*; D008099:Liver / Q000196:embryology / Q000378:metabolism*; D051381:Rats
chemical_list: D002762:Cholecalciferol