title: Oscillating prostacyclin and thromboxane generation by human vessels: biological and mathematical evidence for negative feedback control.
abstract: The presented study investigates the time-dependent release of PGI2 and TXA2 by isolated human umbilical veins in vitro using the radioimmunoassay for measurement. After changing the nutritional fluid--Krebs-Henseleit solution at pH 7.4, 37 degrees C, 95% O2/5% CO2--the release graph oscillates. These oscillations with time were verified by variance analysis and are very similar for both substances. This indicates one or several negative feedback mechanisms acting on the common path of synthesis from the membrane-bound phospholipids to PGH2, which are effective in the regulation of eicosanoid biosynthesis in vitro. A mathematical function describing the observed PGI2 and TXA2 synthesis is communicated.
mesh_terms: D004622:Embryo, Mammalian / Q000502:physiology; D011464:Epoprostenol / Q000032:analysis / Q000378:metabolism*; D005246:Feedback; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008433:Mathematics; D008954:Models, Biological; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D011247:Pregnancy; D011863:Radioimmunoassay; D013928:Thromboxane A2 / Q000032:analysis / Q000378:metabolism*; D013997:Time Factors; D014471:Umbilical Veins / Q000502:physiology*
chemical_list: D013928:Thromboxane A2; D011464:Epoprostenol