Sleep-induced GH release in otherwise GH deficient children having short stature; a possibly new variant of GH neurosecretory dysfunction (GHND).

Sleep and exercise are considered physiologic stimuli of growth hormone (GH) release from the pituitary. They were used to some extent for the assessment of GH reserve in growth disorders of supposedly pituitary origin. In order to better establish the diagnostic value of the sleep test, we studied 34 children of both sexes aged 6-14 having various degrees of shortness of stature associated with bone age retardation (range of the latter: 3-10 years). Eight healthy controls of the same age were also subjected to the sleep test. The latter was begun at 10:00-11:00 a.m. generally in a dark room under polygraphic control. The subjects were fed a standard breakfast at 8:00-8:30 a.m. After thirty minutes of steep or after reaching the IVth stage of slow-wave sleep, the children were awakened and samples of venous blood for GH determinations were drawn. Two other GH reserve tests were also performed in other days, usually insulin-induced hypoglycemia and glycine intravenous loading. Except sleep, no other GH provocative tests were performed in controls. In normal GH reserve children (21/34) according to other tests, the sleep test was positive (i.e. peak values greater than 15 microU/ml) in 7 cases and the mean GH response was not significantly smaller than the peak recorded after insulin-induced hypoglycemia. In abnormal GH reserve, presumably hypopituitary children (13/34) according to other tests, the sleep confirmed the other tests in 8 cases. In five cases of clinically and endocrinologically "hypopituitary" dwarfism, the sleep test revealed a normal response.(ABSTRACT TRUNCATED AT 250 WORDS)