Growth hormone secretion among HIV infected patients: effects of gender, race and fat distribution

Objective: To determine the effects of gender, race, and fat redistribution on growth hormone (GH) secretory patterns in HIV-infectecl patients. Design: We investigated GH responses to growth hormone releasing hormone (GHRH) + arginine stimulation testing in HIV-infected subjects with fat redistribution, comparing HIV-infected males (n=139) and females (n=25) to non HIV-infected male (n=25) and female (n=26) control subjects similar in age, body mass index and race. Methods: A standard GHRH + arginine stimulation test [GHRH 1 mu g/kg and arginine 0.5 g/kg (maximum dose 30 g)] was performed, and fat redistribution was assessed by anthropometry. Results: HIV-infected women had significantly higher peak GH in response to GHRH + arginine (36.4 +/- 7.3 versus 18.9 +/- 2.0 ng/ml; P=0.003) and GH area under curve (AUC) (2679 +/- 593 versus 1284 +/- 133 (mg-min)/dl, P<0.001) compared to HIV-infected men. Among men, a cutoff of 7.5 ng/ml for peak GH response on the GHRH + arginine test achieved good specificity and sensitivity and optimally separated the HIV and control groups (e.g., the failure rates were 37% versus 8%; P=0.004, respectively). Among women, no specific cutoff could be determined to separate the HIV-infected and control subjects. Non-Caucasians demonstrated a higher GH AUC response compared to Caucasians, among the HIV-infected male subjects. In stepwise regression modeling waist-to-hip ratio was most significantly related to peak GH in response to GHRH + arginine in HIV-infected men. Conclusions: HIV-infected men with fat redistribution have significantly reduced GH peak responses and increased failure rates to standardized GH stimulation testing in comparison to healthy male control subjects and to HIV-infected women of similar age and body mass index. GH secretion is related to gender and race in HIV-infected patients. (C) 2006 Lippincott Williams & Wilkins.