Rate of urinary urea output correlates to degree of muscular atrophy induced by triamcinolone acetonide.

1. The effect of administering triamcinolone acetonide (10 mg kg-1 day-1) as seven consecutive single daily subcutaneous injections on urinary urea output and muscular atrophy was studied in rabbits. 2. The ratio of the wet weight of the lateral vastus of the quadriceps muscle to body weight (MI) varied greatly among the rabbits. 3. The ratio of urinary urea output after to before triamcinolone injection correlated significantly to MI. 4. These findings suggest that the ratio of urinary urea output can be used as a predictive index for steroid myopathy.