Steroids in chicken egg yolk: metabolism and uptake during early embryonic development

Nikolaus von Engelhardt*, Rie Henriksen, Ton G. G. Groothuis

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

68 Citations (Scopus)
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Abstract

Effects of maternal hormones may adaptively adjust offspring development to prevailing conditions. However, Darwinian fitness of parents is maximized by investing in more than one offspring while each individual offspring benefits from receiving maximal investment. The control of mother and offspring over hormone-mediated maternal effects is thought to play a key role in the outcome of parent-offspring conflict, but these control mechanisms have hardly been studied.

We investigated the potential embryonic control by analysing the changes in distribution and metabolism of steroid hormones in the egg during the first 6 days of incubation using injections of radiolabelled testosterone and corticosterone in freshly laid eggs. After I day of incubation the highest amount of radioactivity was concentrated in a small area at the top of the yolk. This challenges the use of hormones in oil as mimicking natural exposure. During incubation radioactivity spread within the egg with highest concentrations in yolk and yolk sac and lower concentrations in albumen, embryo, allantois, and amnion. Steroids were metabolised to other unconjugated and conjugated steroids, perhaps facilitating embryonic steroid uptake. Our study shows that the injected radiolabel is metabolised in the egg and taken up by the embryo, giving the embryo potential control over the effects of maternal hormones and thereby limiting maternal control over the outcome of hormone-mediated maternal effects. (C) 2009 Elsevier Inc. All rights reserved.

Original languageEnglish
Pages (from-to)175-183
Number of pages9
JournalGeneral and Comparative Endocrinology
Volume163
Issue number1-2
DOIs
Publication statusPublished - 2009
Event9th International Symposium on Avian Endocrinology - , Belgium
Duration: 11-Jul-200815-Jul-2008

Keywords

  • Maternal hormones
  • Mechanism
  • Uptake
  • Metabolism
  • Embryo
  • MATERNAL HORMONES
  • AVIAN EGGS
  • HEMOGLOBIN SYNTHESIS
  • OFFSPRING PHENOTYPE
  • ESTROGEN-RECEPTOR
  • GALLUS-DOMESTICUS
  • SEX
  • TESTOSTERONE
  • EXPRESSION
  • BIRDS

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