Depression of calcium pump activity in renal cortex of vitamin D-deficient rats with secondary hyperparathyroidism.
To examine the hormonal regulation of the ATP-dependent Ca2+ pump in the kidneys, the ATP-dependent Ca2+ uptake by the basolateral membrane vesicles in the renal cortex was measured using radioactive calcium (45Ca2+) in rats with vitamin D deficiency or rats undergoing thyroparathyroidectomy. The Vmax of the Ca2+ pump activity was increased not only by administering calcitriol, but also by normalizing the serum calcium level in vitamin D-deficient rats. PTH suppressed the Ca2+ pump activity in normocalcemic vitamin D-deficient rats. Thyroparathyroidectomy did not affect the Ca2+ pump activity in the kidneys of normal rats. It was concluded that the ATP-dependent Ca2+ pump activity was depressed by secondary hyperparathyroidism in vitamin D-deficient rats.
Tsukamoto
Y
Y
Department of Medicine, Kitasato University School of Medicine, Kanagawa, Japan.
Tamura
T
T
Saitoh
M
M
Takita
Y
Y
Nakano
T
T
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002117:Calcitriol / Q000494:pharmacology; D002118:Calcium / Q000097:blood / Q000378:metabolism; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism*; D002132:Calcium Radioisotopes; D002462:Cell Membrane / Q000378:metabolism; D006962:Hyperparathyroidism, Secondary / Q000378:metabolism*; D007672:Kidney Cortex / Q000378:metabolism*; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood / Q000494:pharmacology; D016105:Parathyroidectomy; D051381:Rats; D011919:Rats, Inbred Strains; D013965:Thyroidectomy; D014808:Vitamin D Deficiency / Q000150:complications / Q000378:metabolism*
D015220:Calcium Channels; D002132:Calcium Radioisotopes; D010281:Parathyroid Hormone; D000255:Adenosine Triphosphate; D002117:Calcitriol; D002118:Calcium