Luteinizing hormone upregulates NPPC and downregulates NPR3 mRNA abundance in bovine granulosa cells through activation of the EGF receptor.

During folliculogenesis, the luteinizing hormone (LH) surge triggers dynamic events in granulosa cells that culminate with ovulation. The aim of this study was to evaluate if the epidermal growth factor receptor (EGFR) is required for ovulation in cattle, and if it regulates the expression of the natriuretic peptide (NP) system in granulosa cells after gonadotropin-releasing hormone (GnRH)/LH stimulation. It was observed that GnRH induces amphiregulin (AREG) and epiregulin (EREG) mRNA at 3 and 6 h after in vivo treatment, but the expression of these genes was not regulated by atrial (ANP) and C-type (CNP) NPs in granulosa cells cultured in vitro.

Molecular characteristics of granulosa and cumulus cells and oocyte competence in Nelore cows with low and high numbers of antral follicles.

The aims of this study were to investigate whether the number of antral follicles (AF) in the ovaries of Nelore cows is influenced with the developmental competence of oocytes to reach the blastocyst stage and to quantify the mRNA abundance of genes associated with folliculogenesis and oogenesis in granulosa and cumulus cells. A total of 168 cows were distributed into two experimental groups according to the number of AF, low (≤31) and high AF (≥92), which were determined based on the mean number of AF (61.14) ± SD (30.

Reversible meiotic arrest of bovine oocytes by EGFR inhibition and follicular hemisections.

The objective of this study was to investigate the effects of inhibiting the epidermal growth factor receptor (EGFR) pathway on meiosis blockage and resumption, mRNA expression of genes involved in oocyte maturation and cumulus expansion, and embryo development. Bovine cumulus-oocyte complexes (COCs) were cultured for 15 h in the presence of the EGFR inhibitor (AG1478) and follicular hemisections (FHS). Most of the oocytes (89.

Mechanistic target of rapamycin is activated in bovine granulosa cells after LH surge but is not essential for ovulation.

The LH surge induces functional and morphological changes in granulosa cells. Mechanistic target of rapamycin (mTOR) is an integrator of signalling pathways in multiple cell types. We hypothesized that mTOR kinase activity integrates and modulates molecular pathways induced by LH in granulosa cells during the preovulatory period.

Bovine ovarian cells have (pro)renin receptors and prorenin induces resumption of meiosis in vitro.

The discovery of a receptor that binds prorenin and renin in human endothelial and mesangial cells highlights the possible effect of renin-independent prorenin in the resumption of meiosis in oocytes that was postulated in the 1980s.This study aimed to identify the (pro)renin receptor in the ovary and to assess the effect of prorenin on meiotic resumption. The (pro)renin receptor protein was detected in bovine cumulus-oocyte complexes, theca cells, granulosa cells, and in the corpus luteum.

Neospora caninum DNA detection by TaqMan real-time PCR assay in experimentally infected pregnant heifers.

Neosporosis has been considered the main cause of abortion between the first and the second trimester of pregnancy in cattle. Therefore, the objective of this study was to identify the presence of Neospora caninum DNA obtained from experimental models based on the evaluation of different areas of the fetal nervous system and organs from heifers previously inoculated with NC-1 after or before insemination. This study was performed with Hereford × Nelore (n=29) heifers and all animals were considered free of diseases at the beginning of the experiment.