MULTIPLE HORMONE RESISTANCE IN SHORT CHILDREN BORN WITH INTRAUTERINE GROWTH-RETARDATION

Intrauterine growth retardation (IUGR) is encountered in 2.5% (-2 SD) of newborns. Lack of postnatal catch-up growth is found in 8-20%. If G H secretion is increased early postnatally in IUGR, then some persiste ntly short IUGR children may present with GH insufficiency. However, t he mechanism of postnatal catch-up growth is heterogenous. The respons e to GH treatment with regard to plasma IGF-1, GH dose and growth velo city was analyzed in persistently short idiopathic IUGR children and c ompared to GH-deficient (GHD) and familial short stature (FSS) childre n of similar age and degree of short stature. IUGR children require bo th a greater basal and GH-induced plasma IGF-1 in order to achieve a g rowth velocity of similar magnitude to that of FSS and GHD children. T hese data suggest a different sensitivity to GH in IUGR compared to FS S or GHD children, sustaining the hypothesis that these idiopathic IUG R children may be partially IGF-1 resistant. The recent report of part ial insulin resistance in IUGR subjects raises the possibility of an I GF-1 receptor- or post-receptor-mediated defect.