Hoyer C, Grunert E
Dtsch Tierarztl Wochenschr. 1989 Apr;96(4):182-3.
From 47 mature calves ten blood samples were taken during the first six days of life for determination of total estrogen concentrations. Immediately postnatal concentration of total estrogens in blood plasma was high (1093.2 +/- 452.5 pg/ml blood plasma). Total estrogen values increased towards the sixth hour of life (1789.0 +/- 892.2 pg/ml blood plasma), which is thought to be caused by reabsorption of estrogens released from intracorporeal reservoirs. Towards the 48th hour of life total estrogen values decreased. This decrease indicates a progressive depletion of the reservoirs and also metabolisation and elimination of estrogens by the organism. The fact that total estrogens were nearly unchanged from the 4th day of life onwards reveals the approximative completed elimination of estrogens. At no time significant differences of total estrogen concentrations in blood plasma were found between female and male newborn calves.
从47头成熟犊牛中，在出生后的头6天内采集了10份血样，用于测定总雌激素浓度。出生后即刻血浆中总雌激素浓度很高（1093.2±452.5 pg/ml血浆）。总雌激素值在出生后第6小时升高（1789.0±892.2 pg/ml血浆），这被认为是由体内储存库释放的雌激素重吸收所致。到出生后第48小时，总雌激素值下降。这种下降表明储存库逐渐耗尽，同时机体对雌激素进行代谢和清除。从出生后第4天起总雌激素几乎没有变化，这一事实表明雌激素已接近完全清除。在任何时候，雌性和雄性新生犊牛血浆中总雌激素浓度均未发现显著差异。
