Renal function in anorexia nervosa.

Renal function was examined in twelve patients, eight girls and four boys, with anorexia nervosa (AN) ranging in age from 12.6 to 18.2 years. The weight loss at the time of the study averaged 26%. Determinations were made of glomerular filtration rate (GFR), PAH clearance (CPAH) and urinary concentrating capacity. For references the same studies were also carried out in five healthy teenagers. Both GFR and CPAH were generally CPAH as shown by a significantly lower filtration fraction (FF) in AN. Indirect evidence suggests that the low FF could be attributed to reduced water permeability of the glomerular capillary. The urinary concentrating capacity following fluid deprivation was moderately depressed both before and after the administration of vasopressin. The concentrating defect in AN must therefore be primary of renal origin.