Ant. pituitary-extracts, adrenal cortical extract, and some crystalline compounds obtained from the adrenal cortex exert a marked and rapid diabetogenic effect on animals wholly or partially depancreatized. This action was confirmed in ferrets made diabetic by subtotal pancreatectomy. The action of various other steroids on the glycemia, glycosuria, and acetonuria of diabetic ferrets was also studied. Desoxycorticosterone, a substance highly active in maintaining life in adrenalec-tomized animals, had no consistent effect on diabetic symptoms (5-10 mg. per day for 4-9 days in 8 cases). This confirmed various other findings that the diabetogenic action of cortin cannot be attributed to this compound. Progesterone (10-25 mg. per day for 6-12 days in 5 cases) likewise was without significant effect. Estrogens (various esters of estradiol 1-3 mg. per day for 9-16 days in 6 cases), which usually were found to alleviate diabetic symptoms, had the opposite effect in these cases. In 2 cases there was an initial drop in glycosuria, but this was only transitory and the over-all mean effect was a 35% increase in sugar excretion and an enhancement of acetonuria in every case. The results with testosterone pronionate (15-20 mg. per day for 9 days in 4 cases) suggested a slight diabetogenic response.