EFFECTS OF VERAPAMIL ON INTERSTITIAL CELL STEROIDOGENESIS

The effect of verapamil on interstitial cell steroidogenesis was studied. Collagenase‐dispersed interstitial cells were incubated with varying amounts of LH, 8‐bromo‐cyclic AMP, or verapamil. Cyclic AMP and testosterone were determined in media after 4‐hour incubations. Verapamil in the doses of 10‐4 and 10‐5M inhibited LH‐induced testosterone biosynthesis, while 10‐6M verapamil had no effect. The inhibition persisted even though LH was increased 100 fold. Verapamil (10‐5M) also significantly reduced 8‐bromo‐cyclic AMP and 1‐methyl‐3‐isobutylxanthine‐stimulated testosterone formation. Cyclic AMP responses to LH stimulation were enhanced by low doses (10‐6 and 10‐5M), but were inhibited by a higher dose (10‐4M) of verapamil. This study suggests that verapamil blocks LH‐ and 8‐bromo‐cyclic AMP‐induced testosterone formation. In high doses, verapamil also decreases cyclic AMP response to LH stimulation. The main effect of verapamil appears to be beyond cyclic AMP formation. Copyright © 1979, Wiley Blackwell. All rights reserved