Chronic renal failure increases cytosolic Ca2+ of hepatocytes.
Chronic renal failure (CRF) is associated with increased Ca2+ content of liver and reduced hepatic lipase activity. This has been attributed to a rise in cytosolic Ca2+ ([Ca2+]i) of the hepatocytes, but data on this issue are lacking. We examined the [Ca2+]i and ATP content of hepatocytes as well as the activity of Na(+)-K(+)-adenosinetriphosphatase (Na(+)-K(+)-ATPase), Ca(2+)-ATPase, and Na+/Ca2+ exchanger of hepatic membrane vesicles from normal rats, animals with 6 wk of CRF, CRF normocalcemic parathyroidectomized (CRF-PTX) rats, and CRF and normal animals treated with verapamil (CRF-V, normal-V). [Ca2+]i in hepatocytes of CRF rats was higher (281 +/- 7.4 nM) and ATP lower (6.4 +/- 1.8 nmol/mg protein) than in normal (209 +/- 5.3 nM; 12.5 +/- 0.89 nmol/mg protein), CRF-PTX (212 +/- 1.0 nM; 13.7 +/- 0.79 nmol/mg protein), normal-V (215 +/- 2.3 nM; 14.2 +/- 0.77 nmol/mg protein), and CRF-V rats (209 +/- 7.4 nM; 14.8 +/- 0.72 nmol/10(6) cells). The Na(+)-K(+)-ATPase, the maximal velocity of Ca(2+)-ATPase, and the activity of the Na+/Ca2+ exchanger were reduced, whereas the Michaelis constant of Ca(2+)-ATPase was increase in CRF rats compared with the other four groups of rats. The values in the latter groups were not different.(ABSTRACT TRUNCATED AT 250 WORDS)
Klin
M
M
Division of Nephrology, University of Southern California School of Medicine, Los Angeles 90033, USA.
Smogorzewski
M
M
Massry
S G
SG
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism*; D007676:Kidney Failure, Chronic / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000378:metabolism* / Q000473:pathology; D008297:Male; D010281:Parathyroid Hormone / Q000502:physiology; D016105:Parathyroidectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D012964:Sodium / Q000502:physiology; D019831:Sodium-Calcium Exchanger; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D014700:Verapamil / Q000494:pharmacology
D002352:Carrier Proteins; D010281:Parathyroid Hormone; D019831:Sodium-Calcium Exchanger; D000255:Adenosine Triphosphate; D012964:Sodium; D014700:Verapamil; D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium