The purpose of this study is to measure the amount of IGF-1 produced by the body as a result of giving 2 different doses of growth hormone in children for 7 days only. The study investigator hopes to find the most favorable level of IGF-1 generated after 7 days of growth hormone that correlates with good growth of children with kidney disease. Then instead of dosing growth hormone by weight, like is done now, researchers can dose growth hormone by the amount of IGF-1 that the body produces. Being able to dose more effectively will save valuable time for the child to grow and will shorten the overall duration of growth hormone therapy.