Influence of dietary phosphorus depletion on central pathways of intermediary metabolism in rats.

Studies on P depleted rats compared with control animals kept under pair fed conditions were carried out. Dietary P depletion led to reduced weight gain and a decreased food conversion ratio in comparison with pair fed control animals. Higher N retention, higher urea concentrations in plasma, liver and kidney tissues and a significant reduction of renal glutamate dehydrogenase--a central enzyme of amino acid degradation in kidney mitochondria--in P depleted animals indicated changes in N utilization and N excretion. While lipid metabolism was not affected by P depletion, carbohydrate metabolism was substantially changed in the kidney: Activity of fructose diphosphatase was significantly reduced, implicating a reduced gluconeogenesis in P depletion. Possible mechanisms of these metabolic effects in P depletion are discussed.