Modulation of gap junctions in the myometrium of pigs during early gestation, induced abortion and the oestrous cycle.
Myometrial samples were biopsied from pigs at early pregnancy, within 12 h after initiated abortion and at first dioestrus post-abortion. Abortion was induced either with an isolated gram-negative bacterial endotoxin or the prostaglandin (PG) F2 alpha analog cloprostenol. The tissues were quantitatively examined for gap junctions in electron micrographs. Very small numbers of gap junctions were present between smooth muscle cells in myometria at 24-27 days of pregnancy. The cell-to-cell junctions increased both in number and size at abortion, irrespective of the agent used as abortifacient. A low number of gap junctions were recorded in samples obtained after reinitiation of the oestrous cycle. The plasma levels of oestradiol-17 beta were low at the three biopsy procedures while the increased numbers of gap junctions at abortion occurred when significantly high levels of PGF2 alpha concomitantly with withdrawal of progesterone were determined in circulating blood plasma. It remains therefore unclear, which role do oestrogens play in the synthesis of gap junctions at induced abortion.
Rodriguez-Martinez
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H
Cort
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N
D000028:Abortion, Induced / Q000662:veterinary; D000818:Animals; D004031:Diestrus / Q000502:physiology*; D004971:Estrus / Q000502:physiology*; D005260:Female; D007365:Intercellular Junctions / Q000648:ultrastructure*; D009215:Myometrium / Q000648:ultrastructure*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology*; D013552:Swine / Q000502:physiology*