Bolander F F, Ulberg L C, Fellows R E
Endocrinology. 1976 Nov;99(5):1273-8. doi: 10.1210/endo-99-5-1273.
Levels of bovine placental lactogen (bPL) have been measured in the serum of dairy and beef cattle and in the milk and amniotic fluid of pregnant animals with a highly specific radioimmunoassay. In both dairy and beef cows, serum bPL levels remain low (less than 50 ng/ml) during the first two trimesters and then rise rapidly between 160 and 200 days of gestation to a plateau. The bPL levels do not decline prior to parturition. During the last trimester, serum levels in dairy cows, 1103+/-342 ng/ml, are significantly higher than those in beef cattle, 650+/-37 ng/ml (P less than 0.01); furthermore, dairy cows having a high milk production also tend to have high bPL levels. Serum levels are almost twice as high in twin pregnancies and are not correlated with fetal sex or birth weight. bPL levels in milk and amniotic fluid from dairy cattle during the last trimester are approximately 86% and 25% of the serum values, respectively, suggesting that bPL enters these fluids by passive diffusion.
已采用高度特异性放射免疫分析法测定了奶牛和肉牛血清、怀孕动物的乳汁及羊水中的牛胎盘催乳素（bPL）水平。在奶牛和肉牛中，血清bPL水平在前两个孕期一直较低（低于50 ng/ml），然后在妊娠160至200天之间迅速上升至平台期。分娩前bPL水平不会下降。在妊娠晚期，奶牛血清水平为1103±342 ng/ml，显著高于肉牛的650±37 ng/ml（P<0.01）；此外，产奶量高的奶牛往往也有较高的bPL水平。双胎妊娠时血清水平几乎高出一倍，且与胎儿性别或出生体重无关。妊娠晚期奶牛乳汁和羊水中的bPL水平分别约为血清值的86%和25%，这表明bPL是通过被动扩散进入这些液体的。
