Yasuda K, Furukawa M, Johnston J M
Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas 75235-9051, USA.
Biol Reprod. 1996 Jan;54(1):224-9. doi: 10.1095/biolreprod54.1.224.
In the present study we examined the effects of estrogens on plasma platelet-activating factor acetylhydrolase (PAF-AH) activity in pregnant rats in an attempt to further define the role of platelet-activating factor (PAF) in parturition. The plasma PAF-AH activity decreased starting on Day 13 of pregnancy and reached its lowest level by Day 19 (36.5 +/- 5.7 nmol.min-1.ml-1 plasma, mean +/- SD). The maternal plasma PAF-AH activity rapidly increased to 67.3 +/- 3.5 nmol.min-1.ml-1 plasma by Day 2 postpartum, to 88.8 +/- 14.4 by Day 7, and to 109.1 +/- 4.4 by Day 21, returning to nonpregnant levels by Day 35 in the dams that were allowed to nurse through Day 21. The PAF-AH activity did not increase in dams from which the pups were removed 2 days after delivery. When 17 alpha-ethynylestradiol (0.25 mg/kg) was administered s.c. to pregnant rats for 3 days starting at Day 17 of pregnancy, the plasma PAF-AH activity in the animals decreased by 80% on Day 19, and the rats delivered prematurely on Day 21. When a similar dose of 17 alpha-ethynylestradiol was injected into the pregnant rats for 3 days starting on Day 15, the enzyme activity again decreased by approximately 80% on Day 17 and Day 19 of pregnancy; however, it returned to a value similar to that seen in the controls by Day 21, and the time at which the treated rats delivered was similar to that for the control animals. These observations provide further support for a role of PAF and PAF-AH and their possible regulation by estrogens in the initiation and maintenance of parturition.
在本研究中，我们检测了雌激素对妊娠大鼠血浆血小板活化因子乙酰水解酶（PAF-AH）活性的影响，以进一步明确血小板活化因子（PAF）在分娩中的作用。血浆PAF-AH活性从妊娠第13天开始下降，到第19天降至最低水平（36.5±5.7 nmol·min⁻¹·ml⁻¹血浆，均值±标准差）。产后第2天，母体血浆PAF-AH活性迅速升至67.3±3.5 nmol·min⁻¹·ml⁻¹血浆，第7天升至88.8±14.4，第21天升至109.1±4.4，在哺乳至第21天的母鼠中，到第35天恢复到非妊娠水平。分娩后2天摘除幼崽的母鼠，其PAF-AH活性未增加。从妊娠第17天开始，对妊娠大鼠皮下注射17α-乙炔雌二醇（0.25 mg/kg），持续3天，这些动物的血浆PAF-AH活性在第19天下降了80%，并在第21天早产。从妊娠第15天开始，对妊娠大鼠注射相同剂量的17α-乙炔雌二醇，持续3天，在妊娠第17天和第19天，该酶活性再次下降约80%；然而，到第21天，其恢复到与对照组相似的值，且处理组大鼠的分娩时间与对照动物相似。这些观察结果进一步支持了PAF和PAF-AH及其可能受雌激素调节在分娩启动和维持中的作用。
