Growth Hormone (GH) Responses to GH-Releasing Hormone-Arginine Testing in Human Immunodeficiency Virus Lipodystrophy

Abstract

Abstract Prior studies suggest reduced overnight GH secretion in association with excess visceral adiposity among patients with HIV lipodystrophy (LIPO, i.e. with fat redistribution). We now investigate GH responses to standardized GHRH-arginine in LIPO patients (n = 39) in comparison with body mass index- and age-matched control groups [HIV patients without fat distribution (NONLIPO, n = 17)] and healthy subjects (C, n = 16). IGF-I [242 ± 17; 345 ± 38; 291 ± 27 ng/ml (P < 0.05 vs. NONLIPO)] was lowest in the LIPO group. Our data demonstrate failure rates of 18% for the LIPO group vs. 5.9% for the NONLIPO group and 0% for the C group, using a stringent criterion of 3.3 ng/ml for peak GH response to GHRH-arginine (P < 0.05 LIPO vs. C). Using less stringent cutoffs, the failure rate in the LIPO group rises to 38.5% at 7.5 ng/ml. Among the LIPO patients, the peak GH response to GHRH-arginine was significantly predicted by visceral adipose tissue (P = 0.008), free fatty acid (P = 0.04), and insulin level (P = 0.007) in regression modeling controlling for age, body mass index, sc fat area, and triglyceride level. These data demonstrate increased failure rates to standardized stimulation testing with GHRH-arginine in LIPO patients, in association with increased visceral adiposity. The effects of low-dose GH should be assessed in the large subset of LIPO patients with abnormal GH stimulation testing.