CYTOCHROME-P-450 INHIBITORS ATTENUATE THE HYPOTONIC SHOCK-INDUCED INCREASES IN K-PK1 CELLS( EFFLUX IN LLC)

Cell volume regulation in LLC-PK1 cells was evaluated by measuring Rb- 86 efflux (rate constant), used as an indicator of Kf efflux, Hypotoni c shock induced a transient increase in the rate constant which return ed to baseline values after 15 min. ETYA, an arachidonic acid-competit ive antagonist as well as the cytochrome P-450 inhibitors SKF 525-A, c lotrimazole and 7-ethoxyresorufin, inhibited the hypotonic shock-induc ed increment in the rate constant. Arachidonic acid did not change hyp otonic shock-induced increments in K+ efflux, LLC-PK1 cells were unabl e to metabolize C-14-arachidonic acid. We concluded that although arac hidonic acid inhibitors block the hypotonic shock-induced increment in K+ efflux, this effect cannot be related to inhibition of arachidonic acid metabolism.