Comparison of Spontaneous Growth Hormone Secretion during Daytime and Sleep in Children with Short Stature

Abstract

The authors compared diurnal growth hormone (GH) secretion with GH secretion during sleep in 24 children with delayed growth. In group I (children with normal response to provocative tests), the level of daytime secretion was lower than that of nocturnal secretion. In 3 of 9 cases, daytime secretion was abnormal; nocturnal secretion was normal. In 2 cases, diurnal and nocturnal secretion were abnormal, but response to provocative stimuli was normal. In group II (children with a false partial GH deficiency, i.e., with inadequate response to provocative tests, GH peak < 11 ng/ml and normal nocturnal secretion), the results were comparable with those of group I, with extremely low diurnal secretion in 6 of 9 cases. In group III (children presenting true partial GH deficiency, i.e., GH < 11 ng/ml in response to provocative tests together with abnormal nocturnal secretion), both diurnal and nocturnal GH secretion were insufficient, with nonexistent diurnal secretion in 5 of 6 cases. Diurnal secretion does not seem to be a reliable indicator of 24 h spontaneous secretion.