Effect of different levels of intracellular cAMP on the in vitro maturation of cattle oocytes and their subsequent development following in vitro fertilization.
Serum, gonadotrophins, growth factors, and steroid hormones stimulate the in vitro maturation (IVM) of competent oocytes, acting, directly or indirectly, upon the adenylate cyclase pathway to produce the intracellular messenger, cAMP. The intracellular levels of cAMP in cattle cumulus-oocyte complexes (COC) were manipulated by adding to the collection and maturation media invasive adenylate cyclase (iAC), a toxin produced by the bacterium, Bordetella pertussis. High concentrations of iAC (1 or 5 microgram/ml) in the maturation medium inhibited the resumption of meiosis, while low concentrations (0.1 or 0.01 microgram/ml) resulted in high rates of maturation to the MII stage (92.6 +/- 2.5 and 98.5 +/- 1.4% respectively). The same low concentrations of iAC in the maturation medium resulted in rates of development to the blastocyst stage 8 days post insemination (30.1 +/- 4.2 and 45.1 +/- 3.9%, respectively), which were either not different, or significantly better, than those obtained after IVM in medium supplemented only with serum and gonadotrophins (36.1 +/- 2.9%). Finally, the addition of 0.1 microgram/ml iAC and 0.5 mM 3-isobutyl 1-methylxanthine (IBMX) in the collection medium significantly improved the blastocyst rate when IVM was performed in control medium or medium supplemented with 0.01 microgram/ml iAC (31.9 +/- 5.5 vs. 12.1 +/- 1.6 and 45.5 +/- 2.9 vs. 19.1 +/- 2.3% respectively). It is concluded that the maintenance of an optimal intracellular concentration of cAMP before and during IVM ensures a high developmental competence of bovine oocytes matured in medium without serum and hormones. Mol. Reprod. Dev. 54:86-91,1999.
Luciano
A M
AM
Department of Anatomy of Domestic Animals, University of Milan, Milano, Italy.
Pocar
P
P
Milanesi
E
E
Modina
S
S
Rieger
D
D
Lauria
A
A
Gandolfi
F
F
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D037361:Adenylate Cyclase Toxin; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D001755:Blastocyst / Q000378:metabolism; D001886:Bordetella pertussis; D002417:Cattle; D002467:Cell Nucleus / Q000187:drug effects; D002478:Cells, Cultured; D003470:Culture Media; D000242:Cyclic AMP / Q000378:metabolism*; D005307:Fertilization in Vitro; D008540:Meiosis / Q000187:drug effects; D009865:Oocytes / Q000378:metabolism*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010566:Virulence Factors, Bordetella
D037361:Adenylate Cyclase Toxin; D003470:Culture Media; D010726:Phosphodiesterase Inhibitors; D010566:Virulence Factors, Bordetella; D000242:Cyclic AMP; D000262:Adenylyl Cyclases; D015056:1-Methyl-3-isobutylxanthine