ESPE Abstracts

Background: Arginine HCl infusion is commonly used in the diagnostic workup of GH deficiency. There is a paucity of data whether obesity and/or short stature modulate arginine plasma concentration and associated arginine-stimulated GH secretion following a weight-based arginine infusion protocol.

Objective and hypotheses: To study whether auxiological parameters modulate the arginine plasma concentration profile and associated GH secretion in children undergoing arginine stimulation testing.

Method: Retrospective analysis, including 35 short-statured children (24 male; age 10.1±3.5 years; height SDS −3.1±0.6, weight SDS −2.5±1.0; BMI SDS −0.81±0.2). Arginine plasma concentration profile, following intravenous infusion of 0.5 g/kg arginine, was measured using a lithium high-resolution column (Biochrom 30 amino acid analyser); hGH concentration was measured by a highly sensitive ELISA (Mediagnost, Germany).

Results: Peak arginine plasma concentrations were observed 30 min (4980±364 γmol/l) after start of arginine infusion and preceded peak GH concentration (7.5±1.0 ng/ml) at 45 min. Peak arginine plasma concentration correlated both with weight (r=0.464; P<0.01) and height SDS (r=0.407; P<0.05). We found no sex-dependant differences in arginine profile or stimulated GH secretion. In linear regression analyses, weight SDS contributed significantly to the variance in peak arginine concentration (r²=0.13). Furthermore, BMI SDS contributed significantly to the observed variance in peak GH concentration (r²=0.14).

Conclusion: Weight and height are associated with the arginine plasma profile and the stimulated GH response to arginine stimulation testing and thus should be considered in the interpretation of test results.