K+ transport in isolated rat liver cells stimulated by glucagon and insulin in vitro.
Unidirectional K+ fluxes were measured in suspensions of isolated rat liver parenchymal cells incubated with 42K+ in vitro. By tracer exchange analysis fluxes in both directions were estimated to 8-9 10(-12) mol/cm2. Glucagon in concentrations above 2 x 10(-8) M increased both influx and efflux to 160% of control values. Insulin increased influx by 12-14%, whereas efflux was apparently unaffected. Using an extracellular marker 51Cr EDTA, intracellular level of some ions was estimated in isolated liver cells: K+ = 172 mmol/kg water, Na+ = 25 mmol/kg water, Cl = 53 mmol/kg water. Cellular water content: 60%. Incubation with insulin for 1 h increased the intracellular concentration of K+ 1.7 mmol/kg water. The results indicate that glucoagon increased primarily the K+-permeability of the cell membrane, while insulin stimulates active K+ transport into the cell.
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D002712:Chlorides / Q000378:metabolism; D005934:Glucagon / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008297:Male; D011188:Potassium / Q000378:metabolism*; D051381:Rats; D012964:Sodium / Q000378:metabolism
D002712:Chlorides; D007328:Insulin; D005934:Glucagon; D012964:Sodium; D011188:Potassium