No abstract

Disturbances in tryptophan-nicotinamide adenine dinucleotide pathway, seen in pellagrins whose staple is sorghum have been ascribed to an amino acid imbalance caused by excess intake of leucine. Studies in normal human volunteers and in experimental animals have shown that administration of vitamin B6 will counteract some of the metabolic effects of leucine. In view of these observations, two clinical studies were conducted--one to investigate the vitamin B6 nutritional status of pellagrins and the other to determine whether plasma leucine clearance in pellagrins is different from that of normals. Vitamin B6 nutritional status of pellagrins was found to be far from satisfactory, as indicated by elevated levels of xanthurenic acid and kynurenic acid in urine after a tryptophan load and low plasma pyridoxal phosphate levels. Plasma leucine concentrations at 1, 2, and 4 hr after a leucine load were significantly higher in pellagrins than those in normals. Administration of 25 mg of vitamin B6, intramuscularly 30 min before leucine load significantly decreased plasma leucine concentration in pellagrins. However, the leucine concentration at 4th hr did not return to basal level. Administration of vitamin B6 10 TO 20 mg/day orally for 10 to 15 days normalized leucine tolerance in pellagrins. Data presented here suggest that when the diets contain excess leucine, additional amounts of vitamin B6 are required.

1. Effects of incorporating 30 g leucine/kg into diets on quinolinate phosphoribosyl transferase (QPRT; EC 2.4.2.19) activity and leucine aminotransferase (EC 2.6.1.6) activity were studied in groups of rats receiving 5, 30 and 60 micrograms of pyridoxine/10 g diet. 2. The results indicated that 30 g leucine/kg diet significantly reduced the QPRT activity when the diets provided 5 micrograms pyridoxine/10 g and that the effect was only marginal when the diet included 30 micrograms pyridoxine/10 g. The inhibitory effect was completely absent when the diet provided higher amounts of pyridoxine (60 microgram/10 g). 3. These results suggest that additional amounts of pyridoxine are necessary to counteract the effects of excess of leucine in the diet. 4. Leucine aminotransferase activity was increased in rats given diets containing higher amounts of pyridoxine; supplementary leucine also increased the enzyme activity.

BACKGROUND: Fly ash disposal has recently posed a huge environmental problem due to storage, apart from apprehension about possible contamination of soil, crop produce and ground water with toxic trace and heavy metal and radio nuclides. The purpose of the present study was to evaluate nutritional and toxicological aspects of wheat grown on soils treated with fly ash. Wheat was grown on soils with fly ash (200 t ha −1 ) and without fly ash at two different geographical locations in India. One kilogram each of 36 samples randomly collected from three replicates of wheat grown with and without fly ash were subjected to various analytical techniques to determine the nutrient composition, mineral, trace element and heavy metal content. Furthermore, wheat grown on soils treated with fly ash was also incorporated into the diet at 90% level, fed as a feed for 26 weeks to Wistar/NIN rats for protein and toxicological evaluation.