Prostaglandin production by guinea-pig placenta and other uterine tissues during mid-pregnancy.
Prostaglandin (PG) output from cultured placenta, sub-placenta, endometrium and fetal membranes of guinea-pigs was measured on days 22, 29 and 36 of pregnancy to establish the source of increased PGF2alpha production during mid-pregnancy. PGF2alpha and 6-keto-PGF1alpha were produced in larger quantities than PGE2 by the placenta, sub-placenta and endometrium; 6-keto-PGF1alpha was in the major prostaglandin produced by the fetal membranes. The initial outputs of PGF2alpha, PGE2 and 6-keto-PGF1alpha from the sub-placenta, fetal membranes and endometrium either decreased or remained fairly constant between days 22 and 36. In contrast, the initial outputs of PGF2alpha, PGE2 and 6-keto-PGF1alpha from the placenta increased 14.7-, 2.5- and 2.0-fold, respectively, between days 22 and 36, indicating that the placenta is the tissue responsible for the increase in PGF2alpha output from the mid-pregnant guinea-pig uterus. Aristolochic acid (a phospholipase A2 inhibitor) inhibited prostaglandin output from the endometrium, but had a more variable effect in prostaglandin output from the other tissues. Thimerosal (an arachidonic acid uptake inhibitor) inhibited PGF2alpha and PGE2 outputs from the endometrium, but generally potentiated 6-keto-PGF1alpha output and prostaglandin output from the other tissues. Arachidonic acid release for prostaglandin synthesis in the endometrium, but not the placenta, sub-placental or fetal membranes, is apparently dependent upon a constant level of phospholipase A2 activity.
Norman
S J
SJ
Department of Pharmacology, University of Edinburgh Medical School, UK.
Poyser
N L
NL
D000818:Animals; D034341:Aristolochic Acids; D004717:Endometrium / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005321:Extraembryonic Membranes / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D006168:Guinea Pigs; D008297:Male; D010616:Phenanthrenes / Q000494:pharmacology; D010741:Phospholipases A / Q000037:antagonists & inhibitors; D054467:Phospholipases A2; D010920:Placenta / Q000187:drug effects / Q000378:metabolism*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism*; D011453:Prostaglandins / Q000096:biosynthesis*; D013849:Thimerosal / Q000494:pharmacology
D034341:Aristolochic Acids; D004791:Enzyme Inhibitors; D010616:Phenanthrenes; D011453:Prostaglandins; D013849:Thimerosal; C000228:aristolochic acid I; D010741:Phospholipases A; D054467:Phospholipases A2