Selective impairment of growth hormone response to physiological stimuli.

In a consecutive group of 25 children with defective growth being evaluated for growth hormone deficiency, EEG-monitored slow-wave sleep provided discriminatory serum growth hormone responses equivalent to those obtained by arginine and insulin-hypoglycaemia provocation. Exercise was less effective but was able to provide a useful screening test. In 2 subjects with abnormal physiological but normal pharmacological serum growth hormone responses, therapeutic administration of growth hormone in one resulted in a significant growth increment, whereas in the other, advanced epiphyseal maturity precluded adequate evaluation. A normal growth hormone response to a pharmacological stimulus does not exclude a therapeutic response to human growth hormone.