Swelling and cAMP on hyperpolarization-activated Cl- conductance in rat Leydig cells.

We have used the whole cell patch-clamp technique to characterize changes in membrane conductance induced by osmotic swelling in mature rat Leydig cells dialyzed with ATP (control cells) or adenosine 3',5'-cyclic monophosphate (cAMP) plus ATP (cAMP cells). A spontaneous current activation occurs in both groups in isosmotic conditions (300/295 mosM in/out). This development is entirely counteracted in control cells and partly inhibited in cAMP cells by exposing them to a hyperosmotic (350 mosM) bath solution, and these currents increase again in a hyposmotic (205 mosM) bath solution.