Brown G P, Venuto R C
State University of New York, Buffalo 14214.
Am J Physiol. 1990 Mar;258(3 Pt 1):E418-22. doi: 10.1152/ajpendo.1990.258.3.E418.
In pregnant rabbits, systemic levels of prostaglandin E2 (PGE2) are elevated. To evaluate the source of the rise in circulating levels of PGE2, eicosanoid production was determined in rabbit placental cotyledons and the following vascular tissues: mesenteric arteries, main renal arteries, and intrarenal preglomerular vessels (n = 6 or 7 rabbits). Comparisons were made with vascular tissues from nonpregnant rabbits (n = 6 or 7). Freshly isolated tissues were incubated for 15 min at 37 degrees C. Medium aliquots were analyzed for eicosanoids by radioimmunoassay. Maximal net production and release (pg/microgram protein) was determined by subtraction of the quantity of eicosanoids present in medium before incubation from that present at the end of incubation. Net production and release of 6-ketoprostaglandin F1 alpha (PGF1 alpha), a stable metabolite of prostacyclin, and of PGE2 was similar in vascular tissues from pregnant and nonpregnant rabbits. Thromboxane B2 (TxB2) generation in preglomerular vessels from pregnant rabbits was lower (P less than 0.05) than that of nonpregnant rabbits. This could contribute to renal vasodilation in pregnancy. The pattern of eicosanoid production in vascular tissues was 6-keto-PGF1 alpha greater than PGE2 greater than TxB2, and in cotyledons it was PGE2 greater than 6-keto-PGF1 alpha greater than TxB2. In cotyledons, PGE2 and TxB2 production was 56-219 and 2-12 times that in maternal vascular tissues, respectively. These data suggest that physiologically significant quantities of eicosanoids may be released by rabbit placental tissue.
在怀孕的兔子中，前列腺素E2（PGE2）的全身水平会升高。为了评估循环中PGE2水平升高的来源，对兔胎盘小叶以及以下血管组织中的类花生酸生成进行了测定：肠系膜动脉、肾主动脉和肾内球前血管（n = 6或7只兔子）。并与未怀孕兔子的血管组织（n = 6或7只）进行了比较。将新鲜分离的组织在37℃下孵育15分钟。通过放射免疫测定法分析培养基等分试样中的类花生酸。最大净生成和释放量（pg/微克蛋白质）通过从孵育结束时培养基中存在的类花生酸量中减去孵育前培养基中存在的类花生酸量来确定。在怀孕和未怀孕兔子的血管组织中，前列环素的稳定代谢产物6-酮前列腺素F1α（PGF1α）和PGE2的净生成和释放量相似。怀孕兔子球前血管中血栓素B2（TxB2）的生成低于未怀孕兔子（P < 0.05）。这可能有助于孕期肾血管舒张。血管组织中类花生酸的生成模式为6-酮-PGF1α > PGE2 > TxB2，而在小叶中为PGE2 > 6-酮-PGF1α > TxB2。在小叶中，PGE2和TxB2的生成量分别是母体血管组织中的56 - 219倍和2 - 12倍。这些数据表明，兔胎盘组织可能会释放具有生理意义数量的类花生酸。
