Urine metabonomic profiling of a female adolescent with PIT-1 mutation before and during growth hormone therapy: insights into the metabolic effects of growth hormone.

OBJECTIVE: Growth hormone (GH) is a protein hormone with important roles in growth and metabolism. The objective of this study was to investigate the metabolism of a human subject with severe GH deficiency (GHD) due to a PIT-1 gene mutation and the metabolic effects of GH therapy using Nuclear Magnetic Resonance (NMR)-based metabonomics. NMR-based metabonomics is a platform that allows the metabolic profile of biological fluids such as urine to be recorded, and any alterations in the profile modulated by GH can potentially be detected.
DESIGN: Urine samples were collected from a female subject with severe GHD before, during and after GH therapy, and from healthy age- and sex-matched controls and analysed with NMR-based metabonomics.
SETTING: The samples were collected at a hospital and the study was performed at a research facility. PARTICIPANTS: We studied a 17 year old female adolescent with severe GHD secondary to PIT-1 gene mutation who had reached final adult height and who had ceased GH therapy for over 3 years. The subject was subsequently followed for 5 years with and without GH therapy. Twelve healthy age-matched female subjects acted as control subjects. INTERVENTION: The GH-deficient subject re-commenced GH therapy at a dose of 1 mg/day to normalise serum IGF-1 levels. MAIN OUTCOME MEASURES: Urine metabolic profiles were recorded using NMR spectroscopy and analysed with multivariate statistics to distinguish the profiles at different time points and identify significant metabolites affected by GH therapy.
RESULTS: NMR-based metabonomics revealed that the metabolic profile of the GH-deficient subject altered with GH therapy and that her profile was different from healthy controls before, and during withdrawal of GH therapy.
CONCLUSION: This study illustrates the potential use of NMR-based metabonomics for monitoring the effects of GH therapy on metabolism by profiling the urine of GH-deficient subjects. Further controlled studies in larger numbers of GH-deficient subjects are required to determine the clinical benefits of NMR-based metabonomics in subjects receiving GH therapy.