Csapo A I
Prostaglandins. 1977 May;13(5):965-73. doi: 10.1016/0090-6980(77)90226-x.
Following ovariectomy of five New Zealand white rabbits at day 25 of pregnancy, the intrauterine pressure (IUP) and uterine progesterone (P) and prostaglandin (PG) levels were measured sequentially at days 25, 26 and 27. At day 25, when the uterine P and PGE and PGF were high, massive intrauterine treatment with 500 microng PGF2alpha provoked only a sustained contracture on which only low level oscillation in IUP was superimposed. At day 26, when the P levels had decreased significantly (P less than 0.001) and the PG levels had not changed significantly, 50 microng PGF2alpha significantly increased cyclic IUP as compared with the day 25 value (P less than 0.001). At day 27, when the P levels decreased further, as little as 5 microng PGF2alpha provoked still higher cyclic IUP, in spite of a significant reduction in PG levels (P less than o.05). Stretching the uterus of six post partum and six 26 days pregnant rabbits (after removing the uterine contents) significantly increased the uterine PGF levels (P less than o.001). However, stretch increased only cyclic IUP of the post partum uterus and was without effect on the pregnant uterus, which still had high P levels. These results indicate that the myometrium is activated by exogenous PG or stretch, regardless of whether the uterine PG levels increase, remain unchanged or even moderately decrease, provided that the uterine P levels are reduced to a critical value.
在五只新西兰白兔妊娠第25天时进行卵巢切除术，然后在第25、26和27天依次测量子宫内压（IUP）以及子宫孕酮（P）和前列腺素（PG）水平。在第25天，子宫P、PGE和PGF水平较高时，向子宫内大量注射500微克PGF2α仅引起持续性挛缩，IUP仅出现低水平振荡。在第26天，当P水平显著下降（P<0.001）且PG水平无显著变化时，与第25天的值相比，50微克PGF2α使IUP出现明显的周期性变化（P<0.001）。在第27天，当P水平进一步下降时，尽管PG水平显著降低（P<0.05），但仅5微克PGF2α就能引起更高的IUP周期性变化。对六只产后和六只妊娠26天的兔子（去除子宫内容物后）的子宫进行牵拉，显著提高了子宫PGF水平（P<0.001）。然而，牵拉仅增加了产后子宫的IUP周期性变化，对妊娠子宫没有影响，因为妊娠子宫的P水平仍然很高。这些结果表明，无论子宫PG水平升高、保持不变甚至适度降低，只要子宫P水平降至临界值，子宫肌层就会被外源性PG或牵拉激活。
