STIMULATION OF STATURAL GROWTH BY RECOMBINANT INSULIN-LIKE GROWTH FACTOR-I IN A CHILD WITH GROWTH-HORMONE INSENSITIVITY SYNDROME (LARON TYPE)

We studied the effects of 9 months of treatment with twice-daily subcutaneous injections of insulin-like growth factor I (IGF-I), 120 mug/kg per dose, in a 9.7-year-old child with growth hormone insensitivity syndrome, in whom short-term studies had suggested that IGF-I might promote linear growth. Height velocity increased from 6.5 cm/yr (+1.7 SD score) to 11.4 cm/yr (+8.8 SD score). Serum concentrations of IGF-I increased from pretreatment values of 9 +/- 2 mug/L to a peak of 347 +/- 26 mug/L after 2 hours. Serum concentrations of IGF-II were unchanged. Basal but not stimulated growth hormone concentrations were decreased. During the first 12 days of treatment, serum concentrations and the 24-hour urinary excretion of urea nitrogen were decreased by 28% and 10%, respectively (p <0.05), there was a 2.4-fold increase in urinary excretion of calcium (p <0.001), and creatinine clearance and urine volume increased by 22% and 55%, respectively (p <0.02). The changes in serum levels of urea nitrogen and in urinary calcium and creatinine clearance were still evident at 10 weeks. Fasting and postprandial serum glucose concentrations remained normal. We conclude that IGF-I given as twice-daily subcutaneous injections is effective in stimulating statural growth without producing the hypoglycemia and hyperglycemia observed when IGF-I is infused continuously.