[Age characteristics of K(+) transport in the rat distal colon].

In vitro and in vivo experiments with perfusion in 20- and 60-day old rats revealed that K+ absorption in the gut as well as 86Rb uptake in the distal colon was significantly higher in younger rats due probable, to the higher activity of the apex-located K+-dependent ATPase and lower activity of the basolateral K+-carriers. The luminal blockade of K+ absorbing pumps with ouabain or omeprazole resulted in a decrease of the K+ absorption and K2 accumulation in skeletal muscles. The higher K+-absorbing/K_ secreting mechanisms ratio in younger rats contributes to the positive potassium balance.