The basal rate of urea formation 18 hrs. post-operatively was greater in ACTH-treated nephrectomized rats than in control nephrectomized rats. The latter has a higher rate than adrenalectomized-nephrectomized rats. 200 mg. of glucose/100 g. body wt. has no effect on the basal rate of urea formation in the latter 2 groups but reduced that of the ACTH-treated rats to the control level. 500 mg. of glucose/100 g. body wt. decreased the basal rate of urea formation in nephrectomized and adrenalectomized rats. The hourly rate of urea formation after an intraven. injn. of amino acids was decreased during the 1st but not the 2d hr. after injn. in adrenalectomized-nephrectomized rats compared to control or ACTH-treated nephrectomized rats which did not differ in their rates of urea formation after injn. of amino acids. The delayed urea formation after amino acid injn. in the adrenalectomized-nephrectomized rats was not reflected in a delayed fall in blood amino N. 200 mg. of glucose/100 g. body wt. decreased the amt. of urea formed 1 and 2 hrs. after amino acid injn. in control nephrectomized and adrenalectomized-nephrectomized rats but not in ACTH-treated nephrectomized rats. Blood amino N 1 and 2 hrs. after amino acid injn. were higher in the glucose-treated adrenalecto-mized-nephrectomized rats receiving amino acids than in the correspondingly treated control and ACTH-treated nephrectomized rats. The adrenal cortex apparently exerts an influence on amino acid catabolism in the liver as well as on protein catabolism in the periphery; but the former is only apparent by the technics used here in the presence of a plethora of glucose.