Plasma Estrone Levels in the Chick Embryo

Woods, Jennifer; Congoran, Donna D.; Thomes, Robert C.

doi:10.3382/ps.0611729

Cited by 12 publications

(3 citation statements)

References 27 publications

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“…Sexually dimorphic steroid concentrations in incubated eggs could be attributable to any of at least three sources: (i) a maternal sex-determining mechanism; (ii) sex differences in embryonic production of sex steroids, which ultimately accumulate in the yolk; or (iii) sex differences in sequestration or metabolism of sex steroids. Although Petrie et al (2001) emphasize the first explanation, avian embryos are known to produce sexually dimorphic levels of E2 (higher in female embryos) and T (higher in male embryos) by 7.5 days of incubation (Galli & Wasserman 1973;Woods et al 1975;Woods & Brazzill 1981;Ottinger et al 2001). Steroids are lipophilic and highly yolk-soluble, and easily cross biological membranes.…”

Section: Introductionmentioning

confidence: 99%

No sex difference in yolk steroid concentrations of avian eggs at laying

2005

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Yolk steroids of maternal origin have been proposed to influence genetic sex determination in birds, based on sex differences in yolk steroid concentrations of peafowl eggs incubated for 10 days. More recent reports dispute this proposal, as yolk steroids in eggs incubated for 3 days do not show such sex differences. To date, research examining this phenomenon has only analysed incubated eggs, although sex in avian species is determined before incubation begins. This may be a serious methodological flaw because incubation probably affects yolk steroid concentrations. Therefore, we investigated sex differences in yolk steroid concentrations of unincubated avian eggs. We withdrew yolk for steroid analysis from fresh, unincubated Japanese quail (Coturnix japonica) eggs by biopsy, and then incubated those eggs for 10 days, after which we harvested the embryonic material for genetic sexing and the incubated yolk for further steroid analysis. We found no sex differences in fresh Japanese quail eggs; however, sex differences were apparent in yolk steroids by day 10 of incubation, when female eggs had significantly more oestrogen in relation to androgen than male eggs. Concentrations of all yolk androgens decreased dramatically between laying and day 10 of incubation, whereas oestradiol (E2) concentrations increased marginally. Thus, yolk concentrations of androgens and E2 do not appear critical for avian sex determination.

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Section: Introductionmentioning

confidence: 99%

No sex difference in yolk steroid concentrations of avian eggs at laying

2005

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“…We candled eggs regularly to confirm which embryos developed and were alive (Giraldo-Deck, Loveland, Goymann, Tschirren, et al, 2022). In chicken, which have a similar incubation period as ruffs, morphological differentiation of the gonads is completed after day 8.5 of incubation (Smith & Sinclair, 2004), and from then on steroid synthesis and the expression of their receptors increases (Woods, Simpson, & Moore, 1975). At very low expression levels, differences between sexes and morphs would be difficult to detect.…”

Section: Captive Breedingmentioning

confidence: 99%

A supergene affects steroid metabolism during early ontogeny in a bird with alternative reproductive morphs

Giraldo‐Deck

Loveland

Goymann

et al. 2022

Preprint

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Reproductive phenotypes are shaped by genetic, physiological and environmental variation that an organism experiences during ontogeny. Steroid hormones play an integrative role in this process through both genomic and non-genomic pathways. Differences in steroid hormone metabolism may be rooted in genomic variation. Here we evaluate the influence of supergene variants underlying alternative reproductive tactics on sex steroid metabolism during ontogeny in ruffs (Calidris pugnax). Adult ruff males exhibit three male mating morphs called Independents, Faeders and Satellites, that differ prominently in circulating androgen (testosterone and androstenedione) concentrations. Across morphs and sexes chicks showed similar mean androgen concentrations during ontogenetic development. However, variances in circulating androgens showed the same pattern as corresponding variances previously observed in adults. HSD17B2 had been previously identified as a key gene for mediating differences in androgen levels between morphs as it encodes the enzyme that converts testosterone to androstenedione and is located within the supergene. Observed HSD17B2 expression in embryonic brain tissue was consistent with predictions based on genetic and endocrine differences. Taken together, the observed differences in circulating androgen concentrations and gene expression point to testosterone synthesis as a key mechanism that shapes developmental trajectories and differences in brain organization among morphs.

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“…Measurable testosterone was not formed from dehydroepiandrosterone. All (Brown, 1955) (Woods et Brazzill, 1981 ;Woods et al, 19821. A cet égard, les résultats déjà signalés de…”

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Synthèse d'oestrogènes par l'ovaire embryonnaire de Poulet à partir de divers précurseurs radioactifs : comparaison des taux de synthèse

Weniger¹,

Chouraqui²,

Zeis³

1983

Reprod. Nutr. Dévelop.

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Summary. A study of oestrogen synthesis by the chick embryo ovary using various radioactive precursors.The ability of the 17-day old chick embryo ovary to convert radioactive progesterone, testosterone, androstenedione and dehydroepiandrosterone to oestrone and oestradiol was investigated. The conversion rate was highest with dehydroepiandrosterone (13 %). Testosterone was the next best precursor (6.5 %), closely followed by androstenedione (5.1 %), with progesterone giving the lowest rate (0.9 %). The synthesis of oestrogens from dehydroepiandrosterone thus seemed to bypass testosterone and androstenedione.The level of oestradiol synthesis was consistently higher than that of oestrone. Measurable testosterone was not formed from dehydroepiandrosterone. All these results have been discussed in relation with' previously published data.Introduction.

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Plasma Estrone Levels in the Chick Embryo

Cited by 12 publications

References 27 publications

No sex difference in yolk steroid concentrations of avian eggs at laying

No sex difference in yolk steroid concentrations of avian eggs at laying

A supergene affects steroid metabolism during early ontogeny in a bird with alternative reproductive morphs

Synthèse d'oestrogènes par l'ovaire embryonnaire de Poulet à partir de divers précurseurs radioactifs : comparaison des taux de synthèse

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