Elevated basal levels of cytosolic calcium of thymocytes in chronic renal failure.
The basal levels of cytosolic calcium ([Ca2+]i) in rats and/or humans with chronic renal failure (CRF) are elevated in many cells including brain synaptosomes, pancreatic islets, polymorphonuclear leukocytes, platelets and B and T cells. This rise in [Ca2+]i has been attributed to the state of secondary hyperparathyroidism of CRF. These observations have led to the proposition that CRF is a state of cellular calcium intoxication mediated by excess parathyroid hormone (PTH). The documentation of a high basal level of [Ca2+]i in other cells is needed to provide further support for this postulate. The present study evaluated the basal levels of [Ca2+]i of thymocyte, which are targets for PTH action, in normal, CRF, and CRF parathyroidectomized (CRF-PTX) rats. We also examined whether CRF affects the phenotype expression (Thy-1, CD4 and CD8) in thymocytes. The results showed that the basal levels of [Ca2+]i in thymocytes from CRF rats (81 +/- 3.7 nM) are significantly (p < 0.01) higher than those in normal animals (60 +/- 2.9 nM). PTX of CRF animals prevented the elevation in the basal levels of [Ca2+]i of thymocytes; in these animals, the levels were 59 +/- 2.8 nM. Neither CRF nor the elevation in [Ca2+]i of thymocytes affected their phenotype expression.
Stojceva-Taneva
O
O
Division of Nephrology, University of Southern California School of Medicine, Los Angeles 90033.
Smogorzewski
M
M
Fadda
G Z
GZ
Massry
S G
SG
D000818:Animals; D002118:Calcium / Q000097:blood*; D003600:Cytosol / Q000737:chemistry; D016130:Immunophenotyping; D007676:Kidney Failure, Chronic / Q000097:blood / Q000378:metabolism*; D008297:Male; D010281:Parathyroid Hormone / Q000494:pharmacology; D016105:Parathyroidectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013601:T-Lymphocytes / Q000737:chemistry*
D010281:Parathyroid Hormone; D002118:Calcium