Evidence of a role for protein kinase C in epidermal growth factor-induced prostaglandin E2 synthesis in amnion cells
Article Abstract:
Cervical ripening and myometrial (uterine) contractions are needed for delivery. Prostaglandins (PG) are locally produced and locally acting hormones found in tissues throughout the body. Two particular PGs, PGE2 and PGF2-alpha, are important mediators of cervical ripening and myometrial contractions, and a significant portion of these hormones are contributed by the fetal amnion membrane. Studies have suggested that PG secretion is initiated by the action of a protein hormone, epidermal growth factor, which can be produced by fetal kidney and which may act by activating an intracellular protein, protein kinase C. To determine whether the action of protein kinase C is important in stimulating PG production by EGF, the responses of laboratory-grown amnion cells were studied. Direct stimulation of protein kinase C by its fatty activators, phorbol esters, increased PGE2 production by 10-fold or more. Low, non-stimulatory levels of phorbol esters enhanced epidermal growth factor-stimulated PG production. Inhibitors of protein kinase C blocked phorbol ester- and epidermal growth factor-stimulated PG production. Treatment of cells to decrease protein kinase C content led to decreased PG production in response to phorbols but not epidermal growth factor. The results suggest that although protein kinase C probably mediates part of epidermal growth factor activity, there appears to be a protein kinase C-independent stimulation by epidermal growth factor of PG production. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: American Journal of Obstetrics and Gynecology
Subject: Health
ISSN: 0002-9378
Year: 1990
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Morphologic changes in the human amnion epithelium that accompany labor as seen with scanning and transmission electron microscopy
Article Abstract:
The amnion is the inner membrane of the sac in which the fetus grows during pregnancy. The effect of normal, active labor on the ultrastructure, or fine structure, of the human amnion epithelial membrane was assessed. Amnion membranes were obtained after 6 to 12 hours of active labor from patients whose babies were born vaginally, and before clinical signs of labor from patients who delivered their babies by cesarean section. The amnion membranes of women who did not undergo active labor consisted of a single layer of epithelial cells with numerous microvilli, or microscopic projections, in a closely associated cell arrangement. The amnion membranes of patients who experienced active labor consisted of a single layer of epithelial cells interrupted by gaps between the cells and associated with extrusions outside of the cells. The junctions between the cells were less complex in patients who had experienced labor. In addition, the number of lipid (fat) droplets per cell were greater in active labor patients than in patients who did not experience labor. These findings show that morphologic, or physical, changes occur in the amnion membrane during labor; these changes may precede or accompany the biochemical changes associated with childbirth. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: American Journal of Obstetrics and Gynecology
Subject: Health
ISSN: 0002-9378
Year: 1991
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Effect of prolonged oral terbutaline therapy on glucose tolerance in pregnancy
Article Abstract:
Treatment with terbutaline between weeks 24 and 32 of pregnancy may increase the risk of developing glucose intolerance. Terbutaline is taken by pregnant women to prevent premature labor, and previous studies suggested it contributes to gestational diabetes. Seventeen healthy pregnant women took terbutaline for five days. Levels of glucose and insulin and insulin to glucose ratios were significantly higher seven days after treatment initiation than before. Furthermore, these levels remained abnormally high even 7 days after they stopped taking terbutaline. One woman developed gestational diabetes. The high insulin to glucose ratios observed indicate that terbutaline increases levels of glucagon, which increases blood glucose levels, and reduces sensitivity to insulin. These findings suggest that pregnant women taking terbutaline should be tested for glucose intolerance.
Publication Name: American Journal of Obstetrics and Gynecology
Subject: Health
ISSN: 0002-9378
Year: 1993
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