vitamin-k-semiquinone-radical and potassium-superoxide

The influence of the oxidizing agents (H2O2, KO2 and Vitamin K) on the action of vasopressin to guinea pig hepatocytes was investigated from the view-point of cytoplasmic Ca2+ concentration and protein secretion. 10 nmol/l vasopressin brought about increase in prothrombin secretion along with increase in the cytoplasmic Ca2+ concentration compared to the non-stimulation level. The pretreatment of the cells with 1 mumol/l of the oxidizing agents, however, led to suppression of Ca2+ elevation and inhibited the vasopressin-induced prothrombin secretion completely, while no leak if lactic dehydrogenase (LDH), Na+ and K+ were detected. The same results of the inhibition in fibrinogen and albumin secretion were observed. These results suggested a possibility that the oxidizing agents such as the peroxides act on some site of cellular signal transduction system in cell membrane to reduce the cytoplasmic Ca2+ level and to suppress the vasopressin-induced secretion.

Topics: Animals; Calcium; Cytoplasm; Enzyme-Linked Immunosorbent Assay; Guinea Pigs; Hydrogen Peroxide; L-Lactate Dehydrogenase; Liver; Potassium; Prothrombin; Sodium; Superoxides; Vitamin K