Growth hormone release during sleep in growth retarded children

Abstract

Plasma growth hormone (HGH) concentration was measured at frequent intervals during EEG-monitored nocturnal sleep in 12 children of short stature. Sleep-related HGH peaks were compared with peak HGH responses to arginine infusion and to insulin-induced hypoglycaemia. Peak plasma HGH levels during sleep ranged from 26-4 to 36 8 μU/ml in 5 children with constitutional short stature, and from 14 8 to 28 4 μU/ml in 4 children with chronic asthma. 3 hypopituitary children failed to show rises in plasma HGH levels despite EEG-adjudged normal sleep patterns. In the children who were not growth hormone deficient, maximum increases in plasma HGH concentration occurred from 30 to 90 minutes after the onset of sleep, and were associated with slow-wave sleep patterns on the EEG. HGH responses to the pharmacological stimuli were comparable with the sleeprelated HGH peaks in 9 of the 12 patients studied. In 2 patients with constitutional short stature, blunted HGH responses to arginine were associated with normal rise in plasma HGH during sleep and during insulin-induced hypoglycaemia. 1 child with impaired growth after operation for a craniopharyngioma exhibited a normal HGH response to arginine (20 -4 μU/ml), a subnormal HGH response to insulin (7 4 μU/ml), and a peak plasma HGH of 4 μU/ml during sleep. Subsequent treatment with exogenous HGH produced a rapid acceleration in height velocity suggesting that impaired growth was due to growth hormone deficiency. These studies are in accord with the suggestion that sleep-induced HGH release is an index of physiological HGH secretion, and that measurement of HGH release during sleep may prove a valuable tool in the detection of growth hormone deficiency in children of short stature.