1. From the Hypertension-Endocrine Branch (G.Z., F.H.N., L.V.R., L.-N.C., M.J.Q.) and Hematology Branch (M.K.), National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Md; and the Center for Biological Experimental Research (H.M.), Food and Drug Administration, Bethesda, Md.