Reproduction Abstracts

Oocyte–cumulus communication is essential for COC metabolism and oocyte developmental competence. Although the oocyte appears not to be absolutely required for cumulus expansion in cattle, it is not clear whether it influences this process. We tested the effects of oocytectomy on expansion and glucose metabolism of bovine COCs submitted to in vitro maturation (IVM). Follicles 3–8 mm were aspirated from abattoir ovaries and grades 1 and 2 COCs were selected. ...

Oocytes are arrested in prophase I until the LH surge, which stimulates an EGF-like growth factor signaling cascade critical for cumulus expansion, and releases meiotic arrest while inhibiting the expression of natriuretic peptide C (NPPC). In rodents, there is evidence that KIT ligand (KITLG) secreted from granulosa/cumulus cells may also enhance nuclear maturation of the oocyte. The objective of the present study was to measure the expression of KITLG in bovine cumulus–...