Zygote

Exposing bovine cumulus–oocyte complexes to aromatizable androgen restore serum-induced low estradiol production in vitro

M.P. Bernucia1 c1, D.L. Bulgarelia2, A.A. Virequea2, C.P. Pitanguia2, M.F.S. de Saa2 and A.C.J.S. Rosa-e-Silvaa2

a1 Department of Gynecology and Obstetrics, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.

a2 Department of Obstetrics and Gynecology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, 14049–900 Ribeirão Preto, SP, Brazil.

Summary

We aimed in this study to assess whether serum-decreased bovine cumulus–oocyte complex (COC) steroidogenesis during in vitro maturation (IVM) is caused by deficient androgen milieu. For this approach, bovine COCs were cultured in serum-supplemented IVM medium in the presence or absence of 1 μM androstenedione. After 24 h of culture, medium was collected and analyzed for its content of estradiol-17β (E2) and progesterone (P4). Medium E2 content markedly increased after incubation of COCs with androstenedione (17.52 ± 1.86 ng/ml to the androgen group; 0.32 ± 0.05 ng/ml to the non-androgen group). No significant difference in the P4 content was detected despite the presence of androstenedione (21.83 ± 1.61 ng/ml to the androgen group; 21.73 ± 1.67 ng/ml to the non-androgen group). Our data provide compelling evidence that bovine COCs steroidogenesis remains functional during culture in serum-supplemented medium and suggest that serum-induced decreased COCs estradiol secretion is caused by deficiency of an aromatizable androgen source.

(Received February 11 2012)

(Accepted November 23 2012)

(Online publication September 16 2013)

Keywords:

  • Androstenedione;
  • Folliculogenesis;
  • In vitro fertilization;
  • Steroidogenesis

Correspondence

c1 All correspondence to: Marcelo Picinin Bernuci. Department of Obstetrics and Gynecology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, 14049–900 Ribeirão Preto, SP, Brazil. Tel: +55 16 3602 5110. Fax: +55 16 3602 2231. e-mail: mbernuci@usp.br

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