[The partial inhibition of the growth hormone response to growth hormone-releasing hormone after the administration of the calcium antagonist verapamil].

The changes produced by administering a calcium channel antagonist on the releasing of growth hormone (GH) induced by the growth hormone-releasing factor (GHRF), are studied. The study was performed on 7 healthy males between 25 and 35 years old, fasting and in bed. We measured the release of GH after the intravenous administration of 250 micrograms of GHRF on 2 successive occasions; one baseline and the second after 3 previous continuous days of 240 mg/day of verapamil. There were no statistically significant differences between the basal concentrations of GH before and after the administration of verapamil. However, the response of GH to GHRF, measured as maximum increase (before verapamil: 12.5 +/- 5.3; after verapamil: 9.5 +/- 3.9 ng/ml and total increase (before verapamil: 29.6 +/- 12.4; after verapamil: 21.6 +/- 11.9 ng/ml) was significantly lower after verapamil produces a partial blockade of GH release induced by GHRF.