Document Detail

A novel pattern of placental leucine transfer during mid to late gestation in a highly placentotrophic viviparous lizard.
MedLine Citation:
PMID:  22821866     Owner:  NLM     Status:  MEDLINE    
Placentotrophy is the nourishment of embryos by resources provided via the placenta during gestation. The magnitude and timing of placental nutrient support during pregnancy are important for embryonic growth, especially in highly placentotrophic animals such as mammals. However, no study has yet investigated how placental organic nutrient support may change during pregnancy in highly placentotrophic viviparous reptiles. Amino acids are essential nutrients for embryonic growth and leucine is a common amino acid. The magnitude and timing of placental leucine transfer may affect embryonic growth and mass and, therefore, offspring phenotype. In this study, female Pseudemoia entrecasteauxii, a highly placentotrophic viviparous skink, were collected throughout gestation. We injected (3)H-leucine into these gravid females and assessed the transfer of (3)H-leucine into maternal compartments (i.e., the blood and the liver), and into embryonic compartments (i.e., the embryo, the yolk, and the amniotic fluid). At either 60 or 120 min post-injection, the radioactivity in each sample was extracted and then counted, and the transfer ratio was calculated. Our results provide direct evidence that circulating maternal leucine passes through the placenta into the embryos in this species. The relative rate of placental leucine transfer did not alter during mid to late gestation. This suggests the steady somatic growth of the embryos during mid-late pregnancy is dependent upon the placental transfer of nutrients rather than yolk stores. This pattern of placental nutrient support may determine offspring body size at birth and, therefore, offspring fitness in P. entrecasteauxii.
Keisuke Itonaga; Erik Wapstra; Susan M Jones
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Journal of experimental zoology. Part B, Molecular and developmental evolution     Volume:  318     ISSN:  1552-5015     ISO Abbreviation:  J. Exp. Zool. B Mol. Dev. Evol.     Publication Date:  2012 Jun 
Date Detail:
Created Date:  2012-07-23     Completed Date:  2012-11-19     Revised Date:  2013-04-08    
Medline Journal Info:
Nlm Unique ID:  101168228     Medline TA:  J Exp Zool B Mol Dev Evol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  308-15     Citation Subset:  IM    
Copyright Information:
School of Zoology, University of Tasmania, Hobart, Tasmania, Australia.
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MeSH Terms
Analysis of Variance
Animal Nutritional Physiological Phenomena / physiology*
Embryo, Nonmammalian / metabolism*
Leucine / metabolism,  pharmacokinetics*
Lizards / embryology*
Mammals / embryology
Scintillation Counting
Time Factors
Tritium / pharmacokinetics
Viviparity, Nonmammalian / physiology*
Reg. No./Substance:
10028-17-8/Tritium; 61-90-5/Leucine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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