Lead perturbs 1. 25 dihydroxyvitamin D[sub 3] modulation of intracellular calcium metabolism in clonal rat osteoblastic (ROS 17/2. 8) cells
- Albert Einstein College of Medicine, Bronx, NY (United States)
1,25-Dihydroxyvitamin D[sub 3] (1,25(OH)[sub 2]D[sub 3]) is known to modulate Ca[sup 2+] metabolism in several cell types. 1,25(OH)[sub 2]D[sub 3] causes an increase in Ca[sup 2+] influx and probably exerts many of its effects via the Ca[sup 2+] messenger system. Lead (Pb[sup 2+]) interacts with and perturbs normal Ca[sup 2+] signalling pathways; hence, the purpose of this work was to determine if Pb[sup 2+] perturbs 1,25(OH)[sub 2]D[sub 3] modulation of Ca[sup 2+] metabolism in ROS 17/2.8 cells, which express receptors for and respond to 1,25(OH)[sub 2]D[sub 3], and to determine the effect of 1,25(OH)[sub 2]D[sub 3] on Pb[sup 2+] metabolism in these cells. In both cases three kinetic compartments described the intracellular metabolism of the isotope. These data show that 1 [mu]M Pb[sup 2+] inhibits 1,25(OH)[sub 2]D[sub 3] modulated increases in Ca[sup 2+] flux, whereas 5 [mu]M Pb[sup 2+] increases membrane fluxes, all intracellular Ca[sup 2+] pools, and total cell Ca[sup 2+]. In the Pb[sup 2+] metabolism studies it was found that 10 nM 1,25(OH)[sub 2]D[sub 3] increases intracellular Pb[sup 2+]. Pb[sup 2+] appears to disrupt the modulation of intracellular steady-state Ca[sup 2+] homeostasis by 1,25(OH)[sub 2]D[sub 3] in a complex, biphasic manner and may therefore perturb functions that are modulated by 1,25(OH)[sub 2]D[sub 3] via the Ca[sup 2+] messenger system.
- OSTI ID:
- 7033717
- Journal Information:
- Life Sciences; (United States), Vol. 54:19; ISSN 0024-3205
- Country of Publication:
- United States
- Language:
- English
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