[Estimation of growth hormone secretion during sleep as a screening test in the diagnosis of GH deficiency].

Background: Because of many disadvantages of growth hormone (GH) stimulation tests the diagnosis of growth hormone deficiency (GHD) is still problematic for the clinician. THE AIM of the study was the estimation of diagnostic usefulness of the GH provocation tests and basal IGF-I concentration measurement in the diagnosis of GHD.

Material and methods: The study group consisted of 180 children with short stature diagnosed in the Department of Pediatric Endocrinology and Diabetes in the years 1998-2003. Pharmacological stimulation test with insulin, clonidine, glucagon and L-dopa were used. GH concentration in physiological test after the onset of sleep was also measured. In 60 patients IGF-I concentration was estimated. For statistical analysis Spearman test was used.

Results: The highest mean GH concentrations (19.18 microl U/ml) and GH peaks (26.39 microl U/ml) were observed in sleep test. IGF-I concentration was correlated with GH concentration levels in physiological test after onset of sleep (r=0.4; p<0.05).

Conclusions: Sleep is the strongest stimulatory agent for GH secretion. The estimation of GH secretion after the onset of sleep can be used as a screening test in the diagnosis of GHD. Because of many diagnostic problems in estimation of pituitary function the auxologic parameters should be considered as the most important part in the diagnostic work-up of children with short stature due to GHD.