Growth hormone hypersecretion in a girl with McCune-Albright syndrome: comparison with controls and response to a dose of long-acting somatostatin analog.

Abstract

GH every 20 min for 24 h, insulin-like growth factor I (IGF-I), IGF-binding protein 3, and estradiol (E2) were measured in a 7.3-yr-old girl with precocious puberty due to McCune-Albright syndrome (MAS) who developed stigmata of early acromegaly and in 9 other MAS patients who had no signs of acromegaly. To determine whether the MAS patients had subtle abnormalities in GH secretion, a computerized pulse analysis program was used to compare the MAS data with those from 27 control girls with central precocious puberty who had a similar rate of bone age advance, E2, and body mass index. We found no differences in mean GH, GH pulse frequency, pulse height, or pulse area between MAS patients and controls except in patient 1, who had an elevated mean +/- SD GH compared with controls (15.4 +/- 2 vs. 4.8 +/- 2.3 micrograms/L; P < 0.01) and an elevated IGF-I (908 micrograms/L) and IGF-binding protein 3 (5.6 mg/L). None of the GH parameters correlated with body mass index, age, bone age, or E2 levels in either group. The serum GH in patient 1 fell to near-undetectable levels from 60-180 min after a 100-micrograms sc dose of long-acting somatostatin, confirming that this form of therapy can be effective in cases of GH hypersecretion due to MAS.