Yeoh G C, Morgan E H
Biochem J. 1974 Nov;144(2):215-24. doi: 10.1042/bj1440215.
In this study, the incorporation of [(14)C]leucine into albumin and transferrin in early rat foetuses, vitelline plus amniotic membranes, chorioallantoic placenta and perinatal rat liver slices was measured and used to detect and compare the rates of synthesis of the two proteins. Albumin synthesis was detected in the body of foetuses from 13 days gestation onwards. Transferrin synthesis was detected only after day 15. Transferrin synthesis was demonstrable in the membranes but not in the chorioallantoic placenta of all the animals investigated, i.e. from 13 to 19 days gestation. Synthesis of albumin and transferrin by the liver of near-term and postnatal animals was shown to correlate with published data on the parenchymal cell number/unit wet wt. of liver. Near-term foetuses synthesized relatively more transferrin than albumin when compared with 10-day postnatal animals. The serum concentrations of the two plasma proteins were also determined. These increased before term whereas the rate of synthesis of albumin and transferrin declined. Postnatally, plasma albumin concentration increased but transferrin concentration decreased, yet the rates of synthesis of both proteins by the liver increased with age. This lack of correlation between the rates of synthesis of the two proteins and their respective plasma concentrations could be explained in part by their increased stability after birth. There was also evidence that the liver haemopoietic cells took up transferrin although they do not synthesize the protein. Thus the decrease in this population of cells during development could also contribute to the discrepancy between liver synthesis and serum concentrations of transferrin.
在本研究中，测定了[(14)C]亮氨酸掺入早期大鼠胎儿、卵黄囊加羊膜、绒毛膜尿囊胎盘和围产期大鼠肝切片中白蛋白和转铁蛋白的情况，并用于检测和比较这两种蛋白质的合成速率。从妊娠13天起在胎儿体内检测到白蛋白合成。转铁蛋白合成仅在第15天后被检测到。在所研究的所有动物（即妊娠13至19天）中，在膜中可证实有转铁蛋白合成，但在绒毛膜尿囊胎盘中未检测到。近期和出生后动物肝脏中白蛋白和转铁蛋白的合成与已发表的关于肝脏实质细胞数/单位湿重的数据相关。与出生后10天的动物相比，近期胎儿合成的转铁蛋白相对白蛋白更多。还测定了这两种血浆蛋白的血清浓度。这些在足月前升高，而白蛋白和转铁蛋白的合成速率下降。出生后，血浆白蛋白浓度升高但转铁蛋白浓度下降，然而肝脏中这两种蛋白质的合成速率均随年龄增加。这两种蛋白质的合成速率与其各自血浆浓度之间缺乏相关性，部分原因可能是它们出生后稳定性增加。也有证据表明肝脏造血细胞摄取转铁蛋白，尽管它们不合成该蛋白质。因此，发育过程中这群细胞的减少也可能导致肝脏合成与转铁蛋白血清浓度之间的差异。
