IS PROTEIN-KINASE-C-ALPHA (PKC-ALPHA) INVOLVED IN VASOPRESSIN-INDUCEDEFFECTS ON LLC-PK1 PIG-KIDNEY CELLS

The involvement of protein kinase C (PKC) in vasopressin-induced effec ts on renal water reabsorption is still unresolved, Activation of PKC can be detected by its translocation from the cytosol (C) to the plasm a membrane(PM). In LLC-PK1 cells, the redistribution of PKC alpha, a p redominant isoform of PKC detected, was studied utilizing western blot ting after stimulation with vasopressin. Vasopressin (100 mU/ml) faile d to induce a translocation of PKC alpha from the C to the PM. By cont rast, phorbol myristate acetate (BMA, 200 nM), a potent activator of P KC, induced a relocalization of PKC alpha from the C to the PM. After 2 hours of treatment of cells with PMA, PKC alpha was predominantly de tected in the PM and absent from the C. These results suggest that the signal transduction pathway of vasopressin in LLC-PK1 cells does not involve PKC alpha activation and translocation.