Reproducibility of 24-h growth hormone profiles in children.

Abstract

The rate of GH secretion and the pattern of GH peaks were compared in a group of nine prepubertal children during their prepubertal period in repeated 24-h GH profiles. At investigation, the children were 6-13 years old (at first profile 6-11 years old) and of normal height (+/- 2 SD). Two profiles were obtained per child, (with a mean time interval of 1.5 years, range 0.7 to 3.5 years. The calculated GH secretions of the first and second profiles were compared. As a group, no significant differences in secreted amount of GH, when expressed as data from the second profile as a percentage of data from the first profile (93 +/- 8%), number of peaks (98 +/- 7%) or mean peak amplitudes (92 +/- 11%), were obtained. Between the repeated curves of an individual child, maximal difference in secretion, number of peaks and mean peak amplitudes ranged around +/- 30%, with a mean intraindividual cv of 12%. The reproducibility in the peak distribution for all profiles was also analysed. The relative frequencies is a percentage of the GH peak amplitudes and peak widths were virtually identical in the repeated profiles. Reproducibility of the temporal pattern of profiles was analysed using time-series analysis (Fourier analysis) and showed no difference in rhythmicity between the different occasions. In conclusion, a high reproducibility of both GH secretion and GH pattern was found for the whole group of prepubertal children.(ABSTRACT TRUNCATED AT 250 WORDS)