AJP - Regulatory, Integrative and Comparative Physiology, Vol 234, Issue 1 29-R33, Copyright © 1978 by American Physiological Society
Kinetic analysis of calcium desaturation curves from isolated kidney cells
T. Uchikawa and A. B. Borle
This paper provides mathematical solutions for calculating calcium fluxes
and compartments in isolated kidney cells from calcium-45 desaturation
curves. In contrast to other available methods, these solutions allow the
calculation of kinetic parameters even if isotopic equilibrium has not been
reached at the beginning of the desaturation period. To test the validity
of the method, calcium-45 desaturation experiments were performed in
isolated kidney cells after labeling periods of 30, 60, 90, or 120 min.
Even though the calcium-45 desaturation curves differ with different
labeling times, the respective values of the calculated parameters are
practically identical. The optical labeling period was found to lie between
60 and 120 min. Since this new method does not require initial isotopic
steady state, it allows a formal kinetic analysis of tracer desaturation
curves even after short periods of labeling.
