Oscillatory behavior of control-systems of calcium homeostasis in chickens.
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-hydroxyvitamin D3-1-hydroxylase in chicks subjected to a 12:12 h light: dark cycle ALSO followed diurnal oscillations, with a nadir 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 oscillated 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.
Hurwitz
S
S
Institute of Animal Science, Volcani Center, Bet Dagan, Israel.
Miller
B
B
Norman
A W
AW
D000375:Aging / Q000502:physiology*; D000465:Algorithms; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002132:Calcium Radioisotopes; D002478:Cells, Cultured; D002645:Chickens / Q000502:physiology*; D053493:Cholestanetriol 26-Monooxygenase; D003198:Computer Simulation; D005246:Feedback; D006706:Homeostasis; D007668:Kidney / Q000201:enzymology; D007700:Kinetics; D008297:Male; D008954:Models, Biological; D009991:Oscillometry; D010507:Periodicity; D012279:Rickets / Q000378:metabolism; D013250:Steroid Hydroxylases / Q000378:metabolism
D002132:Calcium Radioisotopes; D013250:Steroid Hydroxylases; D053493:Cholestanetriol 26-Monooxygenase; D002118:Calcium