Motta I G, Rocha C C, Bisinotto D Z, Melo G D, Júnior G A A, Nishimura T K, Diaza A M G, Castro T, Ginther O J, Pugliesi G
Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Pirassununga, São Paulo, Brazil.
Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Pirassununga, São Paulo, Brazil; North Florida Research and Education Center, University of Florida, FL, USA.
Domest Anim Endocrinol. 2021 Jul;76:106625. doi: 10.1016/j.domaniend.2021.106625. Epub 2021 Mar 23.
The effects of 17β-estradiol (E2) or estradiol benzoate (EB) on PGF2α release were studied in bred-non-pregnant and pregnant Nelore beef heifers. The day of timed artificial insemination (TAI) was designated day 0 (D0), and a single treatment was given on D14. All heifers also received an intravaginal P4 device on D14, and were randomly assigned to three groups: Control (C, P4 device only, n = 12); E2 (1 mg E2 + 9 mg P4, n = 10); or EB (1 mg, n = 10). Blood samples were collected hourly for 8 hours after treatment (Hours 0-8) to measure plasma concentrations (pg/mL) of a PGF2α metabolite (PGFM). The P4 device was removed on D22 and pregnancy was diagnosed on D28. Pregnancy rate was not different among groups (C, n = 7/12; E2, n = 5/10; EB, n = 5/10). More (P < 0.05) heifers had a CV-identified prominent PGFM pulse (peak of > 100 pg/mL) in E2 group (6/10) than in EB (1/10) and C (0/12) groups. Hourly concentration of PGFM for Hours 0 to 8 showed significant effects of group and hour and an interaction of group by hour but did not show an interaction of group or hour with pregnancy status. In preliminary post-hoc analyses, PGFM concentrations during Hours 0 to 8 and pulse characteristics were analyzed within each pregnancy status. For the non-pregnant heifers, a group-by-hour interaction was detected tentatively indicating an increase (P < 0.005) in PGFM concentrations in E2 group from Hours 4 to 6 and in EB group at Hours 5 and 6. Maximum PGFM concentration during Hours 0 to 8 did not differ (P > 0.1) between E2 (124 ± 23) and EB (110 ± 30) groups, but was greater (P < 0.05) in each group than in C (32 ± 3). Furthermore, PGFM concentrations of pulses at the peak, amplitude, and area under pulse curve (pg/mL/h) were greater (P < 0.05) in E2 group than in C group whereas the EB group did not differ (P > 0.1) from the other groups. For pregnant heifers, no effects of group, hour, or their interaction were detected in PGFM concentrations during the hourly sessions, except that maximum PGFM concentration was greater (P < 0.05) in E2 than in EB and C groups. In addition, the number of prominent pulses was greater in E2 group than in Control or EB groups. In conclusion, PGFM increased earlier and in greater concentration combined for bred-non-pregnant and pregnant heifers treated 14 days after TAI with 1 mg E2 plus 9 mg P4 than with 1 mg EB. Tentatively, a positive effect for each of E2 and EB on PGFM concentrations was attenuated in pregnant heifers.
在非妊娠和妊娠的内罗尔肉牛小母牛中研究了17β-雌二醇（E2）或苯甲酸雌二醇（EB）对PGF2α释放的影响。将定时人工授精（TAI）日定为第0天（D0），并在第14天进行单次处理。所有小母牛在第14天也接受了阴道内P4装置，并随机分为三组：对照组（C，仅P4装置，n = 12）；E2组（1 mg E2 + 9 mg P4，n = 10）；或EB组（1 mg，n = 10）。处理后每小时采集血样8小时（0至8小时），以测量PGF2α代谢物（PGFM）的血浆浓度（pg/mL）。在第22天取出P4装置，并在第28天诊断妊娠。各组之间的妊娠率无差异（C组，n = 7/12；E2组，n = 5/10；EB组，n = 5/10）。与EB组（1/10）和C组（0/12）相比，E2组（6/10）中更多（P < 0.05）的小母牛有CV识别的明显PGFM脉冲（峰值> 100 pg/mL）。0至8小时的PGFM每小时浓度显示出组和小时的显著影响以及组与小时的交互作用，但未显示组或小时与妊娠状态的交互作用。在初步的事后分析中，在每种妊娠状态下分析了0至8小时期间的PGFM浓度和脉冲特征。对于未妊娠的小母牛，初步检测到组与小时的交互作用，表明E2组在4至6小时以及EB组在5和6小时时PGFM浓度增加（P < 0.005）。0至8小时期间的最大PGFM浓度在E2组（124±23）和EB组（110±30）之间无差异（P > 0.1），但每组均高于C组（32±3）（P < 0.05）。此外，E2组脉冲峰值、振幅和脉冲曲线下面积（pg/mL/h）的PGFM浓度高于C组（P < 0.05），而EB组与其他组无差异（P > 0.1）。对于妊娠小母牛，在每小时的时间段内，未检测到组、小时或它们的交互作用对PGFM浓度的影响，只是E2组的最大PGFM浓度高于EB组和C组（P < 0.05）。此外，E2组的明显脉冲数多于对照组或EB组。总之，与1 mg EB相比，在TAI后14天用1 mg E2加9 mg P4处理的非妊娠和妊娠小母牛，PGFM升高更早且浓度更高。初步来看，E2和EB对PGFM浓度的积极作用在妊娠小母牛中减弱。
