ISSN:
0730-2312
Keywords:
diurnal cycles
;
Zeitgeber
;
vitamin D
;
bone
;
hydroxylase
;
renal cells
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
Computer simulation of calcium homeostasis in chicks predicted an oscillatory behavior of bone calcium flow and kidney 25-hydroxyvitamin D3-1 hydroxylase with a periodicity of 56 h and a 9 h phase difference between the two signals. In growing chickens subjected to a light: dark cycle of 22:2 h, and intravenously dosed with 45Ca, the temporal changes in plasma 45Ca could be described by an exponential decline with superimposed diurnal oscillations. The activity of the renal 25-hydpoxyvitamil D3-1-hydroxylase in chicks subjected to a 12:12 h light: dark cycle ALSO followed diupnal oscillations, with a ladir at the beginning of the light period and a peak 12 h later. The production of 1,25-dihydroxyvitamin D3 by primary cultures of chicken kidney cells mscillated with a periodicity of 5.6 h or shorter. It is suggested that despite the differences in phase and periodicity between the simulation predictions and actual results, the oscillations in both 1-hydroxylase and bone calcium flow could be coupled through the hormonal systems involved in regulation of plasma calcium.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcb.240560218
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