The purpose of this study is to examine the short-term effects of two different doses of growth hormone, compared to treatment with growth hormone releasing hormone, on the brain's secretion of growth hormone and the body's glucose metabolism. We hypothesize that growth hormone administration will alter the body's endogenous pulsatile growth hormone secretion and that higher dose growth hormone may decrease insulin sensitivity. We hypothesize that growth hormone releasing hormone will augment endogenous GH pulsatility and be neutral to insulin sensitivity.

The primary objective of this study is to determine the differential effects of growth hormone releasing hormone (GHRH) vs. low dose physiologic growth hormone (GH) vs. higher dose GH treatment and withdrawal on endogenous overnight growth hormone secretion and pulsatility, as well as insulin-stimulated glucose uptake. Subjects with HIV-infection will be randomized to receive one of three treatments: GHRH 2mg/day, or growth hormone 6mcg/kg/day (physiologic "low" dose), or growth hormone 2mg/day ("higher" dose) for 2 weeks. At baseline and after two weeks of treatment, we will assess overnight growth hormone by frequent sampling as well as insulin stimulated glucose uptake by clamp. Subjects will then stop the treatment and will return for an identical assessment after a 2 week withdrawal period.