Increased potency and sustained suppressive actions of a new gonadotropin-releasing hormone (GnRH) antagonist peptide in man.

We have used a new potent GnRH antagonist to assess the efficacy of suppression of gonadotropin secretion in healthy postmenopausal women at three different doses. The Nal-Glu antagonist produced significant suppression of immunoactive and bioactive LH at a 300 micrograms/kg dose throughout the 30-hr sampling interval with only minimal local (skin) histamine release. This increased potency and decreased skin reactivity of the Nal-Glu antagonist make it a drug with potential clinical use similar to the GnRH agonist, but with the advantage of immediate gonadotropin suppression.