The influence of a purified growth hormone prepn. on fasting metabolism of intact and adrenalectomized mice has been investigated. Doses of 200 [mu]g., administered during a 48-hr. fasting period, depressed the rate of N and water loss from liver and carcass of these animals. This relative sparing of N was accompanied by an acceleration of fat metabolism as evidenced by intense fatty infiltration of the livers of fasting animals treated with growth hormone. The accumulation of liver lipid as a result of growth hormone injn. was independent of the presence of the adrenals. Histological examination did not reveal evidence of liver damage. The data support the suggestion that the lipid-mobilizing action of growth hormone may be integrated with its N.sparing effect. The involution of lymphoid tissue in the fasting mouse was independent of the influence of growth hormone, except at very large doses (4 mg./48 hrs.), which accentuated this phenomenon in intact mice. The increase in mass of lymphoid tissue following adrenalectomy was not potentiated by growth hormone admn. during fasting. Analysis of the composition of the lymphoid tissue wt. gain following adrenalectomy yielded evidence that this enlargement conformed to the criteria of true growth.[long dash].