Variable response to a long-acting agonist of luteinizing hormone-releasing hormone in girls with McCune-Albright syndrome.

Six girls with McCune-Albright syndrome were treated for at least 2 months with the long-acting LHRH agonist D-Trp6-Pro9-NEt-LHRH, which previously was found to be an effective treatment for true precocious puberty. Nocturnal and LHRH-stimulated serum gonadotropin levels and plasma estradiol levels were measured before treatment and after 2-3 months of treatment. Five of the six girls had no decrease in serum gonadotropin or plasma estradiol levels during therapy, and their pubertal signs were unaffected by treatment. All five of these girls had serum gonadotropin levels that were within or below the normal prepubertal range. The sixth girl, who had gonadotropin levels in the normal pubertal range before treatment, had decreased serum gonadotropin and plasma estradiol levels during 1 yr of LHRH analog therapy. This was associated with cessation of menses and regression of secondary sexual changes. The failure of LHRH analog to modify the course of precocious puberty in the five patients with prepubertal serum gonadotropin concentrations is further evidence that the mechanism of precocious puberty in most girls with McCune-Albright syndrome differs from that in patients with true precocious puberty.