[The effect of oxytocin on production of free fatty acid in primary human uterine myometrial cell culture].
Oxytocin(OT) is considered to have several activities besides strongly inducing myometrial contraction by activating phosphatidilinositol-specific phospholipase C(PI-PLC). These include reconstructing the phospholipid constituents of the cell membrane and activating a variety of fatty acid producing systems. On the other hand, pregnancy-related steroid hormones which are produced by the fetus, placenta and mother are considered to be closely involved in the maintenance of pregnancy and the initiation of labor. In the present study with cultured myometrial cells, we examined what effect these steroid hormones might exert on the intramyometrial production of fatty acid by OT. Our results confirmed bi-phasic production of arachidonic acid(AA), linoleic acid(LA), palmitic acid(PA), and stearic acid(SA) by OT. Phase 1 was an increasing but transient phenomenon having its peak at 30 sec. It is considered to be derived from phosphatidylinositol bis-phosphate. Phase 2 was a persistent and increasing phenomenon which was initiated after 120 sec. It is considered to be mediated by Ca-dependent phospholipase. We also studied the effect of steroid hormones on the production of fatty acid. For AA, LA, and PA, we confirmed that dehydroepiandrosterone sulfate(DHAS) shortened the time taken in reaching the peak of Phase 1 to half of that of the control, and progesterone(P) extended the time 2-3 fold. These findings suggest that DHAS, P and F might modify the human myometrial construction mechanism as a factor which regulates the quantity and velocity of fatty acid production.
Department of Obstetrics and Gynecology, Nara Medical University.
T
T
Otsuki
M
M
Oku
S
S
Adachi
E
E
Fujii
M
M
Ichijo
K
K
Morimoto
D016718:Arachidonic Acid / Q000096:biosynthesis; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D005230:Fatty Acids, Nonesterified / Q000096:biosynthesis*; D005260:Female; D006801:Humans; D007213:Indomethacin / Q000494:pharmacology; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000096:biosynthesis; D009215:Myometrium / Q000187:drug effects* / Q000378:metabolism*; D010121:Oxytocin / Q000494:pharmacology*; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000378:metabolism; D013268:Stimulation, Chemical
D005230:Fatty Acids, Nonesterified; D008041:Linoleic Acids; D010169:Palmitic Acids; D016718:Arachidonic Acid; D019308:Palmitic Acid; D010121:Oxytocin; D019787:Linoleic Acid; D007213:Indomethacin