In the growth hormone (GH) neurosecretory dysfunction syndrome affecting slowly growing children with delayed bone age, low nocturnal GH secretion is accompanied by normal responses to pharmacological stimuli. We compared plasma vitamin A with physiological nocturnal and stimulated GH secretion in 68 short prepubertal children. Fasting plasma vitamin A correlated with nocturnal GH secretion but not with stimulated GH secretion. Total dietary vitamin A intake was significantly lower in short children with abnormal nocturnal GH secretion than in normal children and in endocrinologically-normal short children. 9 of 12 children with low nocturnal GH secretion and normal stimulated GH peaks who were supplemented with vitamin A 3000 micrograms for 3 months had increased nocturnal GH secretion.