Experimental design of adenine-induced uremic rats. Twelve-week-old male Sprague-Dawley (SD) rats are maintained under a normal MF diet for one week. At age 13 weeks, the animals are divided randomly into four groups: LP diet (group LP), LP diet+0.75% adenine (group Ade), LP diet+0.75% adenine+2.5% glycine (group Gly), and LP diet+0.75% adenine+2.5% l-Lys·HCl (group Lys). At age 18 weeks, the rats are anesthetized and processed.