Thatcher W W, Guzeloglu A, Meikle A, Kamimura S, Bilby T, Kowalski A A, Badinga L, Pershing R, Bartolome J, Santos J E P
Department of Animal Sciences, University of Florida, PO Box 110910, Gainesville, FL 32611-0910, USA.
Reprod Suppl. 2003;61:253-66.
Evidence is presented that bovine somatotrophin (bST) treatment of lactating dairy cows enhances both expression of oviductal insulin-like growth factor II (IGF-II) mRNA and endometrial insulin-like growth factor binding protein 3 (IGFBP-3) mRNA between day 3 and day 7 of the oestrous cycle. mRNA encoding growth hormone (GH) receptor in endometrial tissues increased between day 3 and day 7 of the oestrous cycle. The changes induced by bST treatment may contribute to stimulation of embryo development and increase pregnancy rates in lactating dairy cows. Additive effects of bST and rb interferon tau (rbIFN-tau) to inhibit phorbol ester induction of prostaglandin F2alpha secretion in immortalized bovine endometrial cells indicates that there is interplay between their signal transduction pathways. Non-lactating dairy cows were killed at day 17 after oestrus to evaluate the effects of pregnancy status (cyclic versus pregnant) and bST (bST versus control) treatment on endometrial gene expression. Distinctly different mRNA and protein responses were detected between cyclic and pregnant cows that were related to luteolytic-antiluteolytic drive (that is expression of progesterone receptor, oxytocin receptor, oestradiol receptor alpha and prostaglandin GH synthase 2 (PGHS-2)). The bST-induced changes in PGHS-2 protein (+), oxytocin receptor mRNA (+) and oestrogen receptor alpha protein (+) may potentially affect the mechanisms associated with maintenance of pregnancy. Two experiments were conducted to evaluate whether ovarian follicular suppression induced by biodegradable deslorelin implants would reduce either early or late embryo losses. A 450 microg deslorelin implant used to induce ovulation in a timed insemination programme decreased subsequent follicular development and tended to reduce early embryo losses, whereas a 2.1 mg deslorelin implant failed to reduce late embryonic losses when inserted on day 27 of pregnancy.
有证据表明，在发情周期的第3天至第7天之间，用牛生长激素（bST）处理泌乳奶牛可增强输卵管胰岛素样生长因子II（IGF-II）mRNA和子宫内膜胰岛素样生长因子结合蛋白3（IGFBP-3）mRNA的表达。子宫内膜组织中编码生长激素（GH）受体的mRNA在发情周期的第3天至第7天之间增加。bST处理引起的这些变化可能有助于刺激胚胎发育并提高泌乳奶牛的妊娠率。bST和重组牛干扰素τ（rbIFN-τ）在抑制永生化牛子宫内膜细胞中佛波酯诱导的前列腺素F2α分泌方面具有相加作用，这表明它们的信号转导途径之间存在相互作用。在发情后第17天宰杀非泌乳奶牛，以评估妊娠状态（发情周期与妊娠）和bST（bST与对照）处理对子宫内膜基因表达的影响。在发情周期奶牛和妊娠奶牛之间检测到明显不同的mRNA和蛋白质反应，这些反应与黄体溶解-抗黄体溶解驱动有关（即孕酮受体、催产素受体、雌二醇受体α和前列腺素GH合酶2（PGHS-2）的表达）。bST诱导的PGHS-2蛋白（+）、催产素受体mRNA（+）和雌激素受体α蛋白（+）的变化可能会潜在地影响与维持妊娠相关的机制。进行了两项实验，以评估可生物降解的地洛瑞林植入物诱导的卵巢卵泡抑制是否会减少早期或晚期胚胎损失。在定时授精程序中用于诱导排卵的450微克地洛瑞林植入物减少了随后的卵泡发育，并倾向于减少早期胚胎损失，而在妊娠第27天插入2.1毫克地洛瑞林植入物未能减少晚期胚胎损失。
