Changes in growth hormone concentrations during puberty in adolescents with insulin dependent diabetes

To document the changes in pulsatile growth hormone secretion in diabetic adolescents during puberty, and to investigate their relationship to both metabolic control and stature.

Auxological parameters, overnight growth hormone secretion, fasting IGF-I, hourly glucose and metabolic control were assessed in a group of adolescents with diabetes.

Fifty-two diabetic adolescents (28 males and 24 females) at different pubertal stages and with varying degrees of metabolic control were studied. Ten of those with poor diabetic control were studied on two occasions.

Height and weight measurements, pubertal staging, growth velocity data and bone age estimation were obtained on all the patients. Overnight growth hormone profiles (Pulsar program analysis), glycosylated haemoglobin and fasting IGF-I were performed on all the subjects. Hourly overnight glucose measurements were also obtained on the ten subjects who had two overnight growth hormone studies.

For the whole diabetic growth, GH area under curve (AUC) was maximal in late puberty (pubertal stage 4), and was paralleled by maximal GH peak amplitude. No relationship between GH-AUC and metabolic control was demonstrated. No difference in GH parameters was demonstrated between the male and female subgroups. The relationship between growth hormone secretory parameters and stature was not significant. However, GH-AUC was significantly correlated with growth velocity in the males but not the females.

The pattern of GH secretion in adolescents with diabetes parallels that seen in normal adolescents during puberty, with increases in GH concentration associated with increased GH pulse amplitude. The degree of metabolic control had no effect on this pattern and there was no relationship between GH secretory parameters and stature.