Growth hormone secretory dynamics in Turner syndrome.

We investigated whether a decrease in serum growth hormone contributes to the short stature of adults with Turner syndrome by measuring the 24-hour profile of serum growth hormone in 30 patients aged 2 to 20 years. Growth hormone pulses were defined as a rise from nadir to peak that exceeded three times the intraassay coefficient of variation. Girls with Turner syndrome aged 2 to 8 years did not have statistically different growth hormone levels, peak amplitudes, and peak frequencies compared with those in age-matched controls. By contrast, girls with Turner syndrome aged 9 to 20 years had significantly decreased mean 24-hour growth hormone levels, peak amplitudes, and peak frequencies compared with those in age-matched normal girls. Patients with Turner syndrome of all ages had decreased serum somatomedin-C concentrations and delayed bone ages. We conclude that a relative deficiency of growth hormone in pubertal patients with Turner syndrome may contribute to their adult short stature.