Maintenance of bovine oocytes in prophase of meiosis I by high [cAMP](i)

H. Aktas, M. B. Wheeler, C. F. Rosenkrans, N. L. First, M. L. Leibfried-Rutledge

Research output: Contribution to journalArticle

Abstract

The effects of high intracellular cAMP concentrations ([cAMP](i)) on germinal vesicle maintenance of bovine cumulus-oocyte complexes were investigated, using 8-bromo-3',5'-cAMP (8-Br-cAMP) or an invasive adenylate cyclase from Bordetella pertussis to increase the [cAMP](i). The effects of interactions of these agents with macromolecular supplements in culture medium (fetal calf serum, FCS; polyvinylpyrrolidone, PVP; BSA), and different methods of processing complexes before culture, on subsequent germinal vesicle maintenance by invasive adenylate cyclase were studied. While 8-Br-cAMP was unable to maintain germinal vesicle arrest in the majority of oocytes for 20 h (36% with FCS, 24% with BSA, 18% with PVP), it maintained germinal vesicle arrest in a high proportion of cumulus-enclosed oocytes when BSA or PVP was used (37% with FCS, 52% with BSA, 53% with PVP). The difference in frequency of germinal vesicle maintenance between macromolecular supplements was not related to [cAMP](i) when assayed after culture for 2 h with invasive adenylate cyclase. Complexes processed in whole follicular fluid were not maintained in meiotic arrest (26%) when cultured with invasive adenylate cyclase and PVP. Complexes processed in follicular fluid with 3-isobutyl 1-methylxanthine (IBMX) plus invasive adenylate cyclase were arrested at the germinal vesicle stage at high frequencies (65%), while those processed in IBMX or IBMX plus 8-Br-cAMP-supplemented follicular fluid had intermediate (43% and 49%, respectively) frequencies of intact germinal vesicles. Oocyte complexes processed in follicular fluid supplemented with IBMX and invasive adenylate cyclase formed morulae and blastocysts (27.2%), as did oocytes processed in follicular fluid alone (26%). Phosphoprotein profiles showed that control oocytes and 8-Br-cAMP-treated oocytes share a profile that is different from that of oocytes treated with invasive adenylate cyclase. These results show that increased [cAMP](i) reversibly maintains bovine oocytes in meiotic arrest for an extended period without the occurrence of the post-translational protein modifications observed during meiotic resumption or transient arrest.

Original languageEnglish (US)
Pages (from-to)227-235
Number of pages9
JournalJournal of Reproduction and Fertility
Volume105
Issue number2
DOIs
StatePublished - Jan 1 1995
Externally publishedYes

ASJC Scopus subject areas

  • Physiology
  • Embryology
  • Molecular Biology
  • Obstetrics and Gynecology
  • Developmental Biology

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