Regular fluctuations in growth hormone (GH) release determine normal human growth

Growth hormone (GH) is the principal hormone associated with growth through childhood, but in a normal child the amount of GH secretion does not appear to be critical in the generation of normal growth rates. We have assessed the relationship between growth and urinary GH (uGH) output in a longitudinal study of 29 healthy prepubertal schoolchildren (13 male, 16 female; age 5.7–7.8 years) over 1 year. Height and uGH were measured three times a week. Individual height velocity curves were derived using non-linear regression. Growth was expressed in terms of the total increment over the year (ΔHt, cm), height velocity standard deviation score (HVSDS) and the average size of individual growth spurts. Urinary GH data (ng) were expressed as a weekly average.