NOCTURNAL GROWTH HORMONE SECRETION: CORRELATION WITH SLEEPING EEG IN ADULTS AND PATTERN IN CHILDREN AND ADOLESCENTS WITH NON-PITUITARY DWARFISM, OVERGROWTH AND WITH OBESITY

Abstract

ABSTRACT Half-hourly blood samples and continuous EEG recordings were obtained during nocturnal sleep in ten adults in whom a special sampling system working from the adjacent room was used in order not to disturb the sleep. In nine of the ten adults the first D/E-stage during sleep was accompanied by a significant increase in plasma growth hormone (HGH) (2.5 to 31.8 ng/ml). Of 16 subsequent D/E-stages only three were accompanied by HGH peaks. Similar studies but without EEG recordings were done in 25 children and adolescents. HGH peaks comparable to those seen in adults occurred in normal children, children with constitutional or primordial dwarfism, with retarded growth associated with renal or with miscellaneous diseases and in children with overgrowth. These peaks frequently seemed to coincide with periods of deeper sleep as judged from observation of the children. There was no evidence that HGH peaks occurred less often or were smaller in dwarfed children or that children with overgrowth had higher or more frequent HGH peaks. However, fewer and smaller HGH peaks were seen in obese children, whether or not obesity was associated with overgrowth. There was no correlation between nocturnal HGH peaks and variations in the concentration of blood sugar (BS), free fatty acids (FFA) or immunoreactive insulin (IRI). No apparent correlation could be seen between the height of the nocturnal HGH peaks and the response of plasma HGH concentration to provocative stimuli. It is concluded that nocturnal HGH peaks are related to, but not exclusively determined by phases of slow-wave sleep. They are not due to disturbance of sleep by the sampling procedure. Their pattern is the same in adults, normal children and in children with non-pituitary dwarfism or overgrowth. Obese subjects often have fewer and smaller nocturnal HGH peaks even when obesity is associated with overgrowth.