Zhang Meijia, Tao Yong, Xia Guoliang, Xie Huirong, Hong Haiyan, Wang Fengchao, Lei Lei
Department of Animal Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100094, PR China.
Theriogenology. 2005 Sep 1;64(4):902-16. doi: 10.1016/j.theriogenology.2004.12.012. Epub 2005 Jan 23.
This study examined the effect of atrial natriuretic peptide (ANP) on porcine cumulus-enclosed oocyte (CEO) maturation and cumulus expansion. ANP negatively regulated follicle-stimulating hormone (FSH)-stimulated germinal vesicle breakdown (GVBD; 90.1, 81.2 and 68.2% for FSH, FSH+10nM ANP and FSH+1 microM ANP, respectively), first polar body emission (PB1; 86.1, 75.3 and 53.3% for FSH, FSH+1 nM ANP and FSH+1 microM ANP, respectively) and cumulus expansion (CEI; 3.47, 3.16 and 2.43 for FSH, FSH+1 nM ANP and FSH+1 microM ANP, respectively) in a dose-dependent manner when CEOs were cultured in the maturation medium containing porcine follicular fluid (pFF). This negative effect showed a time-dependent manner after preincubation with 100 nM ANP for 5h (78.4% PB1), 10h (81.7% GVBD and 74.1% PB1), 20 h (78.5% GVBD and 68.9% PB1), and 44 h (75.3% GVBD and 60.5% PB1), respectively. ANP also significantly inhibited FSH-induced porcine oocyte GVBD (47.6% versus 83.8%) and PB1 emission (22.4% versus 45.2%) when CEOs were cultured in pFF-free maturation medium. cGMP analog 8-Br-cGMP (10 microM to 1mM) mimicked the effects of ANP on GVBD, PB1, and CEI. The negative effect of ANP was completely reversed by KT5823 (a specific inhibitor of cGMP-dependent protein kinase), while C-ANP-(4-23) (an analogue of ANP and specific binder for natriuretic peptide receptors-C) was ineffective in oocyte maturation. Neither ANP nor C-ANP-(4-23) had an effect on spontaneous porcine oocyte maturation and cumulus expansion. These results suggested that ANP negatively regulates FSH-activated porcine oocyte meiotic resumption, meiotic maturation and cumulus expansion. The function of ANP on porcine oocyte maturation is via the cGMP dependent protein kinase (PKG) pathway.
本研究检测了心房钠尿肽（ANP）对猪卵丘-卵母细胞复合体（CEO）成熟及卵丘扩展的影响。当CEO在含猪卵泡液（pFF）的成熟培养液中培养时，ANP以剂量依赖方式对促卵泡激素（FSH）刺激的生发泡破裂（GVBD；FSH、FSH + 10 nM ANP和FSH + 1 μM ANP组分别为90.1%、81.2%和68.2%）、第一极体排放（PB1；FSH、FSH + 1 nM ANP和FSH + 1 μM ANP组分别为86.1%、75.3%和53.3%）及卵丘扩展（CEI；FSH、FSH + 1 nM ANP和FSH + 1 μM ANP组分别为3.47、3.16和2.43）产生负调控作用。当用100 nM ANP预孵育5小时（PB1为78.4%）、10小时（GVBD为81.7%，PB1为74.1%）、20小时（GVBD为78.5%，PB1为68.9%）和44小时（GVBD为75.3%，PB1为60.5%）后，这种负效应呈时间依赖性。当CEO在无pFF的成熟培养液中培养时，ANP也显著抑制FSH诱导的猪卵母细胞GVBD（47.6%对83.8%）和PB1排放（22.4%对45.2%）。环磷酸鸟苷类似物8-溴环磷酸鸟苷（8-Br-cGMP，10 μM至1 mM）模拟了ANP对GVBD、PB1和CEI的作用。ANP的负效应被KT5823（一种环磷酸鸟苷依赖性蛋白激酶的特异性抑制剂）完全逆转，而C-ANP-(4 - 23)（ANP的类似物及钠尿肽受体C的特异性结合剂）对卵母细胞成熟无效。ANP和C-ANP-(4 - 23)对猪卵母细胞自发成熟及卵丘扩展均无影响。这些结果提示，ANP对FSH激活的猪卵母细胞减数分裂恢复、减数分裂成熟及卵丘扩展起负调控作用。ANP对猪卵母细胞成熟的作用是通过环磷酸鸟苷依赖性蛋白激酶（PKG）途径实现的。
