Effect of plasma levels of parathyroid hormone on NADPH pathways in kidney and liver.
NADPH available for mixed function oxidations (pathway 1) or biosynthetic processes (pathway 2) has been evaluated in different cells from rat liver and kidney. In addition, changes of the proportion of NADPH utilized in each pathway were demonstrated in the same cells from rats showing different circulating levels of parathyroid hormone (PTH). Quantitative levels of NADPH directed into each of these pathways have been measured and histologically located in sections from rat liver and kidney using quantitative cytochemistry and scanning and integrating microdensitometry. Centrilobular hepatocytes utilize the major amount of NADPH, either via pathway 1 or 2. Kidney cells utilize most NADPH via pathway 2, particularly in the distal part of the nephron. The cells of the pars recta have shown the highest capacity to utilize NADPH via pathway 1, which is about half that of centrilobular hepatocytes. In centrilobular cells, the presence of high plasma levels of PTH results in a significant increment of NADPH utilization either via pathway 1 or 2. In kidneys from rats showing high plasma levels of PTH, a selective increase in NADPH utilized via pathway 2 was observed in the distal convoluted tubule whereas a selective increase in NADPH utilized via pathway 1 was demonstrated in cells of the pars recta. These observations provide further information in the understanding of the physiology of kidney and liver cells.
D000818:Animals; D003720:Densitometry; D005260:Female; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000378:metabolism; D009249:NADP / Q000378:metabolism*; D009399:Nephrons / Q000378:metabolism; D010084:Oxidation-Reduction; D010281:Parathyroid Hormone / Q000097:blood*; D010427:Pentose Phosphate Pathway; D051381:Rats; D011919:Rats, Inbred Strains
D010281:Parathyroid Hormone; D009249:NADP; D006899:Mixed Function Oxygenases; D005954:Glucosephosphate Dehydrogenase