Comparison of the growth-promoting effects of insulin-like growth factor I and growth hormone in the early years of life.

AIMS: Four infants with isolated growth hormone deficiency (IGHD) and five with Laron syndrome (LS) were studied. Birth length ranged from -2.5 to -4.5 SDS in both groups.

RESULTS

Untreated IGHD children decreased in length from -2.5 to -5.2 SDS at 1 y and to -5.7 SDS at 2 y. Human growth hormone (hGH) treatment (0.07 U/kg/d) increased height by 1.2-2.4 SDS in 3 y. Untreated children with LS decreased in length from -3.5 to -6.5 SDS. Insulin-like growth factor (IGF)-I treatment (150-200 microg/kg/d) in 3 LS patients increased height by 0.5-1.5 SDS in 3 y. All untreated infants had borderline or below normal head circumferences. Both treatments induced a rapid catch-up in head size. In the two untreated LS patients, head circumference remained subnormal.

CONCLUSIONS

Despite similar birth length, infants with IGHD responded better to hGH in terms of linear growth than did infants with LS to IGF-I, whereas the response in brain growth was similar.