Abstract
Objective To determine the effects of gender, race, and fat redistribution on growth hormone (GH) secretory patterns in HIV-infected patients.
Design We investigated GH responses to 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, BMI, and race.
Methods A standard growth hormone releasing hormone (GHRH) GHRH + arginine stimulation test [GHRH 1 μg/kg and arginine (0.5 g/kg, maximum dose 30 g)] was performed, and fat redistribution was assessed by anthropometric measurements.
Results Waist to hip ratio (WHR) was markedly different between male HIV-infected and control subjects and between female HIV-infected and control subjects (0.99 ± 0.01 vs 0.91 ± 0.01, p < .0001 for males and 0.94 ± 0.02 vs 0.85 ± 0.01, p = .0001 for females, HIV vs controls, respectively, in each comparison). HIV-infected women had significantly higher peak GH in response to GHRH + arginine (36.4 ± 7.3 vs 18.9 ± 2.0 ng/mL, p = .003) and GH area under the curve (AUC) (2,678.8 ± 593.3 vs 1,283.8 ± 133.4 mg/dL*min, p < .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 (eg, the failure rates were 37% vs 8%, p = .004, respectively). Among women, no specific cutoff could be determined to separate the HIV and control subjects. Non-Caucasians demonstrated a higher GH AUC response compared to Caucasians among the HIV-infected male subjects. In stepwise regression modeling WHR 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 BMI. GH secretion is related to gender and race in HIV-infected patients.