Calcium homeostasis and parturient hypocalcemia: an integral feedback perspective.
Calcium is tightly regulated in mammals because of the critical role of calcium ion concentrations in many physiological functions. In this work, we develop a model for calcium homeostasis and identify integral feedback control as a functional module that maintains this homeostasis. We argue that maintaining calcium concentrations in a narrow range and perfect adaptation seen when the calcium homeostatic mechanism is subjected to extreme disturbances are the result of a feedback control system implementing integral control through specific interactions of the regulating hormones. Based on the constraints imposed by the suggested integral control, we arrive at a simple dynamical model for calcium homeostasis. We show that the model is biologically plausible and is consistent with known physiology. Furthermore, the utility of the integral-feedback model is revealed by examining an extreme calcium perturbation, parturient paresis in dairy cows.
El-Samad
H
H
Electrical and Computer Engineering, Iowa State University, Ames, IA 50011, USA.
Goff
J P
JP
Khammash
M
M
D000818:Animals; D002118:Calcium / Q000097:blood*; D002417:Cattle; D002418:Cattle Diseases / Q000097:blood*; D005246:Feedback; D005260:Female; D006728:Hormones / Q000502:physiology; D006996:Hypocalcemia / Q000097:blood / Q000662:veterinary*; D008954:Models, Biological; D010319:Parturient Paresis / Q000097:blood*; D011247:Pregnancy
D006728:Hormones; D002118:Calcium