THE EFFECT OF LOW-PROTEIN DIET ON THE EPI THELIUM OF NEPHRON SEGMENTSIN SHEEP

Changes in the epithelium thickness of proximal and distal convoluted tubule of cortex, thin descending limb of Henle loop from inner stripe of outer medulla, thick ascending limb from outer stripe of outer med ulla and of collecting duct from inner medulla were investigated in yo ung growing sheep fed a low protein diet (LP). Sheep on LP-diet were g iven a daily ration with 5.73 g of nitrogen and 6.13 MJ of digestible energy (DE) while the daily intake of control group was 19.51 g of N a nd 12.29 MJ of DE. Both groups of animals were fed these diets at leas t 6 weeks before collection of kidneys. Morphometric analysis with dig itizing tablet showed that intake of LP-diet resulted in significant r eduction of epithelium thickness in both distal convoluted tubule and thick ascending limb while the epithelium of collecting duct was found to be thicker. No changes of the epithelium dimensions were determine d in proximal tubule and in thin descending limb of Henle loop. Presen ted results point to the morphological expression of the adaptation of sheep kidneys to a low dietary protein intake which is associated wit h the increased renal reabsorption of urea.