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Yolk contributes steroid to the multidimensional endocrine environment of embryos of Niveoscincus metallicus, a viviparous skink with a moderately complex placenta

journal contribution
posted on 2023-05-18, 00:15 authored by Laura ParsleyLaura Parsley, Erik WapstraErik Wapstra, Susan JonesSusan Jones
Maternally-derived testosterone (T) and 17-β-oestradiol (E2) provide epigenetic mechanisms by which mothers can actively influence offspring phenotype. In amniotes, maternal steroids may be derived from yolk or transferred across the placenta according to parity mode. Viviparous reptiles utilise both a yolk and a placenta to support their developing embryos, but it has not yet been confirmed whether yolk is a source of maternal T and E2 in such species. We investigated this question using the viviparous lizard Niveoscincus metallicus as our model species. We measured T and E2 in the yolks during vitellogenesis, immediately post-ovulation and at progressive stages of gestation. Our results confirm that yolk is a substantial source of T and E2 in N. metallicus. Contrary to the pattern seen in many oviparous species, we did not observe a marked decline in yolk concentrations of either T or E2 after the initiation of sexual differentiation in the embryos. Rather, we found no statistically significant decline in yolk concentrations of both T and E2 post-ovulation. In viviparous reptiles that utilise both yolk and placenta to nourish their embryos, yolk likely plays an important role in these dynamics but that role is not yet clear. Further research is warranted to understand the importance of yolk steroids in the endocrine environment of the developing viviparous reptile.

Funding

Australian Research Council

History

Publication title

Comparative Biochemistry and Physiology Part A

Volume

171

Pagination

51-56

ISSN

1095-6433

Department/School

School of Natural Sciences

Publisher

Elsevier Science Inc

Place of publication

360 Park Ave South, New York, USA, Ny, 10010-1710

Rights statement

Copyright 2014 Elsevier Inc.

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the environmental sciences

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