SHOULD GROWTH HORMONE DOSES BE INCREASED DURING PUBERTY?

Abstract

Physiological growth hormone (GH) secretion increases during puberty and it has been suggested that similar changes should be made to the therapeutic schedules of GH-insufficient children receiving GH therapy. We have tested this hypothesis in 50 GH-insufficient children aged between 9.7 and 14.5 years who were randomised to continue with biosynthetic human GH at a dose of 15 U/m2 /week (Group A) or to an increased dose of 30 U/m2 /week (Group B), at breast stage 2 development in girls and at a testicular volume of 8 mls in boys. All children had received GH treatment prior to randomisation for at least 1 year. There was no difference between the groups prior to randomisation in terms of age, height and height velocity. Puberty was entered at a similar mean age: 11.8 years (SEM 0.3) in A and 12.0 (SEM 0.2) in B. Despite a 100% increase in GH dose similar growth accelerations of 7.2 (SEM 0.5) (A) and 7.1 (SEM 0.4) cms/year (B) were observed. The net height gain 2 years into the study was similar at 12.7 and 13.8 cms respectively. Both doses of GH led to a significant acceleration in the time taken to progress between genitalia stage 2/breast stage 2 and genitalia stage 4/breast stage 4 compared to Tanner standards (average acceleration 0.3 years). These data suggest that increasing the dose of GH in puberty to mimic the physiological situation does not lead to a significant improvement in growth rate and statural gain. Both doses appear to accelerate the rate at which the individual progresses through puberty which might have important implications for the total height gain expected.