Stable Potassium Isotopes (⁴¹K/³⁹K) Track Transcellular and Paracellular Potassium Transport in Biological Systems

Analysis of urinary potassium isotopes and association with pancreatic health: healthy, diabetic and cancerous states

“…While channels transport K + passively and thermodynamically downhill along the cell membrane, K + transport via pumps is an active and thermodynamically uphill process. Higgins et al (11) proposed that these two groups of K + cell transporters induce different K isotopic effects. While large isotope fractionation should be associated with K + transport via channels, small isotope fractionation is expected for K + transport through pumps (11).…”

“…Higgins et al (11) proposed that these two groups of K + cell transporters induce different K isotopic effects. While large isotope fractionation should be associated with K + transport via channels, small isotope fractionation is expected for K + transport through pumps (11).…”

“…Outliers (°) have been excluded from the statistical calculations; "x' reflects average values; *p < 0.05, **p < 0.01. -0.78 (-0.87, -0.69) -0.80 (-0.94, -0.66) -0.58‰ (-0.72, -0.30) K isotopes (11) and re-absorption preferentially retains 41 K in the body. The trend in higher d 41 K for PDAC compared to healthy controls does not follow the expected K isotopic shift.…”

“…K isotope ratios for various minipig brain regions were found to range from −0.80 to −0.34‰, with a variability of ∼0.5‰ between different brain regions. Higgins et al (11) described that the differences in K isotope fractionation is caused by the different classes of K + transporter and their role in our body. It has been proposed that K + transport via active channels and pores is associated with kinetic isotope fractionation, while transport via passive pumps and cotransporters causes negligible isotope effects (11).…”

“…Higgins et al (11) described that the differences in K isotope fractionation is caused by the different classes of K + transporter and their role in our body. It has been proposed that K + transport via active channels and pores is associated with kinetic isotope fractionation, while transport via passive pumps and cotransporters causes negligible isotope effects (11). Until now only one study has surveyed K isotope composition associated to cancer, which showed similar d 41 K for blood samples from cancer and control patients (12).…”