USDA-ARS, Fort Keogh Livestock and Range Research Laboratory, Miles City, MT 59301, USA.
J Anim Sci. 2011 Apr;89(4):1035-41. doi: 10.2527/jas.2010-3433. Epub 2010 Dec 10.
Oligonucleotide microarrays (GeneChip Bovine Genome Arrays, Affymetrix Inc., Santa Clara, CA) were used to evaluate gene expression profiles in anterior pituitary glands collected from 4 anestrous and 4 cycling postpartum primiparous beef cows to provide insight into genes associated with transition from an anestrous to a cycling status. Tissues were collected 40 to 61 d after calving from anestrous cows and from cyclic cows between d 7 and 13 of the estrous cycle (luteal phase) from d 54 to 77 after calving. Hybridization signals were normalized across arrays, and genes with mean differences in expression that were at least 1.5-fold apart and with a minimum difference in mean signal intensity of 10 were compared. Based on these criteria, 47 transcripts were increased (P < 0.025) and 31 transcripts were decreased (P < 0.025) in pituitary gland tissue from cycling compared with anestrous cows. Few transcripts identified in this analysis were associated previously with reproductive function. To provide greater detail on the influence that stage of the estrous cycle (i.e., collection during the luteal phase) might have on the differences detected in gene expression, quantitative real-time PCR was used to compare gene expression in anterior pituitaries of anestrous cows with an additional independent set of anterior pituitary glands collected at 4 different stages of the estrous cycle: 0.5 to 2 d (n = 9), 5 to 6.5 d (n = 5), 11.4 to 13.7 d (n = 5), and 17.9 to 19 d (n = 6) after the onset of estrus. Gastrin-releasing peptide, the gene that exhibited the largest fold increase in expression in the microarray experiment, and IGFBP3 mRNA were expressed at greater (P < 0.004) amounts in samples from the different stages of the estrous cycle than in samples from anestrous cows. In addition, expression of IGFBP3 mRNA was proportional to serum progesterone concentrations throughout the estrous cycle (P < 0.05). Expression of versican mRNA was decreased (P = 0.03) in samples from the different stages of the estrous cycle compared with anestrous cow samples. Results identified numerous genes that may be involved in the transition from anestrous to cycling status, providing novel insight into mechanisms regulating reproductive function.
寡核苷酸微阵列（GeneChip Bovine Genome Arrays，Affymetrix Inc.，Santa Clara，CA）用于评估产后初产奶牛 4 头乏情和 4 头发情后的前垂体组织中的基因表达谱，以深入了解与乏情到发情状态过渡相关的基因。组织采集于产后 40 至 61 天的乏情牛和产后 54 至 77 天发情周期（黄体期）第 7 至 13 天的循环牛。跨阵列标准化杂交信号，表达差异至少为 1.5 倍且平均信号强度差异至少为 10 的基因进行比较。根据这些标准，与乏情牛相比，发情牛的垂体组织中 47 个转录本（P < 0.025）增加，31 个转录本（P < 0.025）减少。在这项分析中鉴定的少数转录本以前与生殖功能有关。为了更详细地了解发情周期阶段（即在黄体期采集）对基因表达检测到的差异的影响，使用实时定量 PCR 比较了乏情牛的前垂体中基因表达，并使用另外一组独立的前垂体样本进行了比较在发情周期的 4 个不同阶段采集：发情后 0.5 至 2 天（n = 9），5 至 6.5 天（n = 5），11.4 至 13.7 天（n = 5）和 17.9 至 19 天（n = 6）。在微阵列实验中表达量增加最大的胃泌素释放肽（GRP）基因和 IGFBP3 mRNA 在发情周期不同阶段的样本中的表达量高于乏情牛样本。此外，IGFBP3 mRNA 的表达与发情周期中的血清孕酮浓度成正比（P < 0.05）。发情周期不同阶段的样本中 versican mRNA 的表达减少（P = 0.03）与乏情牛样本相比。结果确定了许多可能参与从乏情到发情状态过渡的基因，为调节生殖功能的机制提供了新的见解。
