Nyctohemeral secretion of growth hormone in normal children of short stature and in children with hypopituitarism and intrauterine growth retardation.

A continuous blood sampling technique has been used to monitor human growth hormone (GH) during sleep in fourteen normal short children (age range 6.5-15.0 years), twelve hypopituitary children (2.8-17.3 years), three children with psychosocial GH deficiency (4.0-13.0 years), and three children with intrauterine growth retardation (9.5-11.3 years). The mean GH level of a 5 h sleep period (22.30-03.30 hours) was used to represent the GH response to sleep. The GH response to insulin induced hypoglycaemia (IST) was also determined. In normal short children there was a significant relationship between 5 h mean GH levels and chronological age. The curve defining this relationship was similar to the third centile linear growth velocity curve. The 5 h mean GH levels of the hypopituitary and psychosocial GH deficiency children were more than 2 SD below the age related mean established for normal short children. The children with intrauterine growth retardation demonstrated values which were more than 2 SD above the age related mean.