“…Sex differences in the enzyme architecture of the rat kidney have been known for a long time [1], Especially the effect of the male sex ual hormone on the histology of the kidney and on the activity of certain enzymes has been extensively studied [7,8,20,22,23,25]. Thus, it was shown that the administration of testosterone causes renal hypertrophy and in creases the protein content of the kidney [2,6,9,24], However, nothing is known about the cause of sex differences in the urinary output of enzymes, e.g., yGT.…”