Effect of cycloheximide on the LH release induced by a superactive analog of LH-RH

The effect of cycloheximide on the pituitary response to a superactive analog of LH-RH (D-Ala-6-des-gly-10-LH-RH-ethylamide) was studied in intact male rats. Cycloheximide did not modify the LH release induced by the LH-RH analog within 1 hr after its injection, but produced significant supression between 1 and 4 hr. It is concluded that the early release of LH observed after the administration of the analog occurs from the readily releasable pool of LH in the pituitary gland, which is not affected by cycloheximide. The subsequent LH release that can be suppressed by cycloheximide comes from the second pool of LH.