Janowski T, Zduńczyk S, Podhalicz-Dziegielewska M, Raś A, Chmielewski A
Division of Clinical Endocrinology, Faculty of Veterinary Medicine, University of Agriculture and Technology, Olsztyn, Poland.
Zentralbl Veterinarmed A. 1995 Jul;42(5):345-50. doi: 10.1111/j.1439-0442.1995.tb00386.x.
The present study was designed to examine the effect of systemic oestrone infusion on the course of late pregnancy and parturition, steroid hormone concentrations and maturation of placentomes in cows. Twelve pluriparous pregnant cows with known breeding dates were used in this experiment. Starting on day 267 of pregnancy six cows (experimental group) received 20 mg oestrone daily (in four doses) infused into the vena jugularis until parturition. Six other cows infused with vehicle served as control. Concentrations of oestrone (E1), oestrone sulphate (E1S) and progesterone (P4) were measured by RIA, and after parturition placentomes were examined histologically. In experimental and control animals parturition occurred on days 276,9 +/- 1.8 and 277,2 +/- 1.1 of gestation, respectively. The concentrations of E1 in the treated group were higher (8-12 ng/ml) than those in control animals (1-3 ng/ml), while the levels of E1S (8-14 ng/ml) were similar for both groups. The concentrations of P4 in experimental and control cows were typical for late pregnancy (4-6 ng/ml), with a sharp drop of this hormone 1-2 days before calving. The histological pictures of placentomes obtained from both groups of animals were similar and maturation of the placenta was observed. These results suggest that the prepartal increase of oestrone in maternal plasma does not play a major role in the regulation of parturition and placental maturation.
本研究旨在探讨全身性注入雌酮对奶牛妊娠后期进程、分娩、类固醇激素浓度及胎盘小叶成熟的影响。本实验选用12头已知配种日期的经产怀孕奶牛。从妊娠第267天开始，6头奶牛（实验组）每天（分4次）经颈静脉注入20毫克雌酮直至分娩。另外6头注入赋形剂的奶牛作为对照。采用放射免疫分析法测定雌酮（E1）、硫酸雌酮（E1S）和孕酮（P4）的浓度，分娩后对胎盘小叶进行组织学检查。实验组和对照组动物分别在妊娠第276.9±1.8天和第277.2±1.1天分娩。治疗组的E1浓度（8 - 12纳克/毫升）高于对照组动物（1 - 3纳克/毫升），而两组的E1S水平（8 - 14纳克/毫升）相似。实验组和对照组奶牛的P4浓度在妊娠后期均属正常（4 - 6纳克/毫升），在产犊前1 - 2天该激素急剧下降。两组动物胎盘小叶的组织学图像相似，均观察到胎盘成熟。这些结果表明，母体血浆中分娩前雌酮的增加在分娩和胎盘成熟的调节中不起主要作用。
