Growth and metabolism of the ovine placenta during mid-gestation
Growth and metabolism of the ovine placenta during mid-gestation
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DOI：
10.1016/0143-4004(95)90016-0
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发表时间：
1995-12-01
期刊：
影响因子：
3.8
通讯作者：
Bell, AW
中科院分区：
文献类型：
--
作者：
Ehrhardt, RA;Bell, AW
在本研究中，羊胎盘生长迅速增加然后停止的时间和代谢基础以及伴随的组织细胞结构的变化仅被定义。胎盘生长从妊娠第40天开始迅速进行，在第75-80天达到顶点，此后至第100天观察到组织干物质含量无变化。这些宏观的生长模式是类似于以前观察到的，但目前的结果定义了一个早期的胎盘质量的顶点。根据Gompertz方程，胎盘的绝对生长速率在第55天附近达到最大值，同时在第50天至第60天之间出现最大增生生长期。从第40-50天，DNA合成和组织质量/细胞核数迅速增加，随后增殖生长至第70天。净细胞增殖在第80天明显停止，如DNA含量的顶点所示，趋向于静态的、低速率的DNA合成的开始，持续到第100天。蛋白质合成分数（K-s）和吸积分数（K-g）的变化模式相似，表明K-s的变化可以解释K-g的大部分变化。本研究通过对绵羊胎盘细胞生长关键时期的鉴定，为进一步研究胎盘生长调控机制奠定了基础。
The timing and metabolic basis for the rapid increase then cessation of placental growth in sheep and the accompanying changes in tissue cellularity mere defined in the present study. Placental growth proceeded rapidly from day 40 of gestation to an apex at day 75-80 with no change is tissue dry matter content observed thereafter to day 100. These macroscopic growth patterns are similar to those observed previously, but present results define an earlier apex in placental mass. Absolute growth rate of the placenta reached a maximum near day 55, as derived from the Gompertz equation, concomitant with a period of maximum hyperplastic growth between days 50 and 60. A rapid increase in DNA synthesis and tissue mass per nuclei number from day 40-50 was followed by proliferative growth to day 70. Net cellular proliferation apparently ceased by day 80 as indicated by the apex in DNA content tend the beginning of a static, low rate of DNA synthesis that continued to day 100. Patterns of change in the fractional rates of protein synthesis (K-s) and accretion (K-g) were similar suggesting that changes in K-s explain much of the change in K-g. This study, through its identification of key phases in the cellullar growth of the ovine placenta, has laid the foundation for future research on mechanisms of placental growth regulation.