Albino rats of a defined tribe were made corticoid-osteoporotic by experiment. A control group was treated with 1-methyl-androst-1-enolon at the same time. After killing the animals, the X-ray extinction of the first lumbal vertebra was measured. The contents of calcium of the same vertebra was determined chemically. With both methods we had findings of an osteoporosis in the animals treated with cortisone, and no findings in the animals treated simultaneously with the anabolic hormone.