Insulin-like growth factor I (IFG.I) and IGF-binding protein 3 response to growth hormone is impaired in HIV-infected children.

To better characterize the somatotropic axins in HIV-infected children the circadian thythm of growth hormone (GH), and basal and stimulated (by an insulin-like growth factor I (IFG-I) generation test) plasma levels of IGF-I and insulin -like growt factor-binding protein 3 (IGFBP-3), were evaluated in 16 children (9 boys and 7 girls; age range, 7-11 years) with HIV infection. All patients were free from active opportunistic infection or liver disease at the time of the study. Sixteen age- and sex matched healthy children (10 boys and 6 girls; age range, 7-11 years) served as control subjects. GH rhythmometric data were analyzed by single and population mean consinor analysis. As regards the IGF-I generation test, biosynthetic human GH(hGH, 0.1 IU/Kg, 0.033 mg/kg) was administered subcutaneously for 4 days and blood samples were taken from fasting subjects at baseline and on the morning after the last GH injection for measurement of IGF-I and IGFBP-3. Plasma GH levels fell within normal limits in the HIV-seropositive patients and were similar to those of healthy children (1.31 +/- 1.18 vs. 1.57 +/- 1.16 icrog/liter, respoctively; mean +/- SD). The population mean cosinor analysis shows that the GH circadian thythm reached statistical significance bothe in the HIV-seropositive children and the control Group. Despite this, the IGF- and IGFBP-3 levels were significantly lower in HIV-infected children than in the control Group (75.6 +/- 57.2 vs 233.3 */- 52.5 ng/ml, p < 0.001 and 2.9 +/- 0.17 vs 3.89 +/- 0.24 mg/liter, p < 0.01, respectively; mean +/- SD); moreover, the response of IGF-I and IGFBP-3 to the IGF-I generation test was significantly lower in HIV-infected children than in the control Group (86.3 +/- 55.8 vs 257.5 +/- 53.4 ng/ml, p < 0.001 and 3.14 +/- 0.43 mg/liter, p <0.01, respectively; mean +/- SD). it appears that circadian GH secretion is normal in children with HIV infection, but the response to exogenous GH with regard to IGF-I and IGFBP-3 production is impaired, indicating a degree of GH insensitivity in such children.