Zhuang L Z, Li R H
Laboratory of Reproductive Biology, Institute of Zoology, Academia Sinica, Beijing, PRC.
Sci China B. 1991 Sep;34(9):1092-7.
The capability of cytotrophoblast cells to produce hCG, progesterone, estrogen, cGnRH and beta-endorphin in vitro has been demonstrated in serum-free culture medium. Before experiment, a 24-h preculture was carried out in order to remove the endogenous hormones of the tissue. During a period of 8 days' culture, the cytotrophoblast cells could constantly produce a small amount of hCG. The production of progesterone rose rapidly and became doubled within six days. The estrogen secretion showed a similar pattern in the presence of androstenedione, a precursor of estrogen, indicating the elevation of aromatase activity in the cells. The elevation of the enzyme activity has been further demonstrated not to be induced by androstenedione. In both cytotrophoblast and syncytiotrophoblast cell cultures, cGnRH was only detected in the culture of cytotrophoblast cells, with a value up to 4 pg/10(5) cells/24 h. However, beta-endorphin was identified both in cytotrophoblast and syncytiotrophoblast cells. Its content increased significantly in the medium of cytotrophoblast cell culture from the 4th to 6th days, but declined in the medium of syncytiotrophoblast cell culture. The results demonstrate clearly that the cytotrophoblast cells are the sole origin of GnRH in human placenta and are also able to synthesize beta-endorphin and steroid hormones. The findings indicate that there is no such a sharp functional demarcation existing between these two kinds of trophoblast cells as suggested before. The data are of significance for a better understanding of the mechanism of hormonal regulation in placenta.
在无血清培养基中已证实细胞滋养层细胞在体外具有产生人绒毛膜促性腺激素（hCG）、孕酮、雌激素、促性腺激素释放激素（cGnRH）和β-内啡肽的能力。实验前，进行了24小时的预培养以去除组织中的内源性激素。在8天的培养期内，细胞滋养层细胞能够持续产生少量的hCG。孕酮的产生迅速增加，在6天内翻倍。在雌激素前体雄烯二酮存在的情况下，雌激素分泌呈现相似模式，表明细胞中芳香化酶活性升高。进一步证明这种酶活性的升高不是由雄烯二酮诱导的。在细胞滋养层细胞和合胞体滋养层细胞培养物中，仅在细胞滋养层细胞培养物中检测到cGnRH，其值高达4 pg/10(5)个细胞/24小时。然而，在细胞滋养层细胞和合胞体滋养层细胞中均鉴定出β-内啡肽。其含量在细胞滋养层细胞培养物的培养基中从第4天到第6天显著增加，但在合胞体滋养层细胞培养物的培养基中下降。结果清楚地表明，细胞滋养层细胞是人类胎盘中GnRH的唯一来源，并且还能够合成β-内啡肽和甾体激素。这些发现表明，这两种滋养层细胞之间不存在如之前所认为的那样明显的功能划分。这些数据对于更好地理解胎盘激素调节机制具有重要意义。
