Change in energy reserves in different segments of the nephron during brief ischemia

• Published in: Kidney international Vol. 31; no. 6; pp. 1239 - 1247
• Main Authors: Bastin, Jean, Cambon, Natalie, Thompson, Martha, Lowry, Oliver H., Burch, Helen B.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01-06-1987; Nature Publishing
• Subjects: Adenosine Triphosphate - metabolism; Animals; Biological and medical sciences; Creatine Kinase - metabolism; Energy Metabolism; Glucose - metabolism; Glycogen - metabolism; Ischemia - metabolism; Kidney - blood supply; Kidney Glomerulus - blood supply; Kidney Glomerulus - metabolism; Kidney Medulla - blood supply; Kidney Medulla - metabolism; Kidney Tubules - blood supply; Kidney Tubules - metabolism; Kinetics; Lactates - metabolism; Lactic Acid; Male; Medical sciences; Nephrology. Urinary tract diseases; Nephrons - blood supply; Nephrons - metabolism; Nephropathies. Renovascular diseases. Renal failure; Phosphocreatine - metabolism; Rats; Rats, Inbred Strains; Renovascular diseases; Vertebrata; Experimental disease; Mammalia; Urinary system disease; Ischemia; Rat; Rodentia; Cardiovascular disease; Metabolism; Kidney
• ISSN: 0085-2538; 1523-1755
• DOI: 10.1038/ki.1987.137

Change in energy reserves in different segments of the nephron during brief ischemia. Rat kidneys were made ischemic for 5 to 120 seconds. Segments of individual nephrons were dissected from freeze dried sections and analyzed for ATP, phosphocreatine, glycogen, glucose, glucose-6-phosphate, lactate and creatine kinase. ATP fell most rapidly in proximal convoluted and straight tubules (PCT, PST) and distal convoluted tubules (DCT), and most slowly in glomerulus and papilla. Phosphocreatine levels ranged fivefold and was highest in DCT, where it approached that of brain. Creatine kinase ranged 100-fold with lowest level in PCT, where the ischemic fall in phosphocreatine was so slow as to suggest a function other than that of an energy reserve. Glycogen varied tenfold from modest levels in distal segments to very low levels in PST, and was not used rapidly in any segment. Glucose consumption and lactate production were most rapid in distal portions. High–energy phosphate consumption for the first 7.5 seconds of ischemia, calculated from these data, indicates roughly–equal energy metabolism in proximal and distal segments, with lower levels in papilla, and especially in glomerulus. The absolute values suggest that the in vivo metabolic rate of the nephron continued almost unabated for 5 or 10 seconds of ischemia.