Ovine placental steroid synthesis and metabolism in late gestation

Lawrence P. Reynolds, Erin L. Legacki, C. Jo Corbin, Joel S. Caton, Kimberly A. Vonnahme, Scott D Stanley, Alan J Conley

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Steroid synthesis is required for pregnancy maintenance and for parturition, but comparatively little is known about the major metabolic routes that influence circulating concentrations. Dietary intake changes progesterone and estradiol concentrations in pregnant ewes but whether this reflects placental synthesis is unknown. Progesterone metabolism by 5alpha-reduction is a major metabolic route in other species and can influence the onset of parturition. Therefore, studies were conducted to (1) determine placental enzyme activity, progesterone, and estradiol measured by immunoassay in late gestation ewes on low-, moderate-, and high-nutritional planes, (2) to assess the significance of 5alpha-reduction of progesterone in determining progesterone concentrations in late gestation ewes (gestation day 145) given finasteride to inhibit 5alpha-reductase metabolism. In the second experiment, steroid profiles were examined comprehensively in blood and tissues by liquid chromatography tandem mass spectrometry for the first time in this species. Dietary intake altered progesterone and estradiol serum concentrations but without correlated changes in placental 3beta-hydroxysteroid dehydrogenase, 17alpha-hydroxylase/17,20-lyase cytochrome P450 or aromatase activity. 5alpha-reduced pregnane metabolites were identified in ewes at 145 days of gestation, but concentrations were lower than those of progesterone. Finasteride inhibited 5alpha-reduced progesterone metabolism but did not impact serum progesterone concentrations in these ewes. We conclude that (1) diet-induced changes in serum progesterone and estradiol concentrations are not likely a result of altered placental synthesis of sex steroid but most likely by their metabolism, and (2) metabolism by 5α-reduction is not a major determinant of systemic progesterone concentrations in late gestation ewes.

Original languageEnglish (US)
Pages (from-to)662-670
Number of pages9
JournalBiology of Reproduction
Volume99
Issue number3
DOIs
StatePublished - Sep 1 2018

Fingerprint

Progesterone
Sheep
Steroids
Pregnancy
Estradiol
Finasteride
Serum
Parturition
Pregnancy Maintenance
Steroid 17-alpha-Hydroxylase
Pregnanes
Aromatase
Tandem Mass Spectrometry
Mixed Function Oxygenases
Immunoassay
Liquid Chromatography
Cytochrome P-450 Enzyme System
Oxidoreductases
Diet
Enzymes

ASJC Scopus subject areas

  • Reproductive Medicine
  • Cell Biology

Cite this

Ovine placental steroid synthesis and metabolism in late gestation . / Reynolds, Lawrence P.; Legacki, Erin L.; Jo Corbin, C.; Caton, Joel S.; Vonnahme, Kimberly A.; Stanley, Scott D; Conley, Alan J.

In: Biology of Reproduction, Vol. 99, No. 3, 01.09.2018, p. 662-670.

Research output: Contribution to journalArticle

Reynolds, LP, Legacki, EL, Jo Corbin, C, Caton, JS, Vonnahme, KA, Stanley, SD & Conley, AJ 2018, 'Ovine placental steroid synthesis and metabolism in late gestation ', Biology of Reproduction, vol. 99, no. 3, pp. 662-670. https://doi.org/10.1093/biolre/ioy089
Reynolds LP, Legacki EL, Jo Corbin C, Caton JS, Vonnahme KA, Stanley SD et al. Ovine placental steroid synthesis and metabolism in late gestation Biology of Reproduction. 2018 Sep 1;99(3):662-670. https://doi.org/10.1093/biolre/ioy089
Reynolds, Lawrence P. ; Legacki, Erin L. ; Jo Corbin, C. ; Caton, Joel S. ; Vonnahme, Kimberly A. ; Stanley, Scott D ; Conley, Alan J. / Ovine placental steroid synthesis and metabolism in late gestation In: Biology of Reproduction. 2018 ; Vol. 99, No. 3. pp. 662-670.
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