Biochemical controls: potassium regulation (Introduction)

by David Turell , Monday, January 30, 2023, 23:58 (445 days ago) @ David Turell

Both too low and too high can kill:

https://www.sciencedaily.com/releases/2023/01/230130090355.htm

"Potassium, a common mineral abundant in food like bananas and leafy greens, is essential to normal cellular function. It helps the cardiac muscle work correctly and aids in the transmission of electrical signals within cells.

"Using existing biological data, researchers at the University of Waterloo built a mathematical model that simulates how an average person's body regulates potassium, both in times of potassium depletion and during potassium intake. Because so many foods contain abundant potassium, our bodies constantly store, deploy, and dispose of potassium to maintain healthy levels -- a process known as maintaining potassium homeostasis. Understanding potassium homeostasis is essential in helping diagnose the source of the problem when something goes wrong -- for example, when kidney disease or medication leads to dysregulation.

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"The model could be used for a virtual patient trial, allowing researchers to generate dozens of patients and then predict which ones would have hyper- or hypokalemia based on different controls.

"'A lot of our models are pieces of a bigger picture," said Anita Layton, professor of applied mathematics and Canada 150 Research Chair in mathematical biology and medicine. "This model is one new and exciting piece in helping us understand how our incredibly complex internal systems work."

"The model is especially exciting because it allows scientists to test something called the muscle-kidney cross-talk signal hypothesis. Scientists have hypothesized that skeletal muscles, which are responsible for most of the potassium storage in the body, can directly signal to the kidneys that it's time to excrete excess when too much potassium is stored, and vice versa. When the math researchers tested the hypothesis in their model, it more accurately reflected existing biological data regarding potassium homeostasis, suggesting that muscle-kidney cross talk might be an essential piece in the puzzle of potassium regulation."

Comment: potassium is a key intracellular constituent while sodium is in higher concentration outside cells. Potassium is stored largely in muscle cells as the article
notes. Feedback loops manage the controls both at the cellular and renal levels. These controls cannot be evolved stepwise, but must be designed because they are irreducibly complex.