THE DISTRIBUTION OF ENZYMES IN THE KIDNEYS OF SHEEP FED A HIGH AND LOW-PROTEIN DIET

The distribution of 13 enzymes in the cortex, in the outer medulla and in the inner medulla of kidneys was investigated in sheep fed a high (HP) and low (LP) protein diet Sheep on HP-diet were given a daily rat ion with 150.2 g of crude protein (CP) and 15.2 MJ of digestible energ y (DE) while the daily intake of sheep on LP-diet was 58.3 g of CP and 14.2 MJ of DE. Both groups of animals were fed these diets for at lea st 6 weeks before the collection of kidneys. Histochemical analysis of enzymes showed that glucose-6-phosphatase and 5'-nucleotidase were no t detectable in the kidney of sheep fed the HP-diet but they appeared in both the cortex and the outer stripe of the outer medulla of sheep On the LP-diet. Alkaline phosphatase of the inner stripe of the outer medulla and of the base of papilla was found in sheep fed the HP-diet only. Adenosine triphosphatase of the inner medulla appeared in sheep fed the LP-diet only. Changes in the distribution of other studied enz ymes were only of a small magnitude. The present results demonstrate t he enzyme expression of metabolic adaptation of sheep kidney to a low protein intake associated with an increased renal urea reabsorption.