Chloride and potassium activities in luminal fluid of turtle thyroid follicles as determined by selective ion-exchanger microelectrodes.
Cl(-) and K(+) activities in the follicular lumen and the intraluminal potential of the same lumen were measured simultaneously with specific liquid ion-exchanger and 3 M KCl microelectrodes, respectively, in turtle thyroid glands. The Cl(-) equilibrium potential between the thyroid interstitium and the lumen calculated from the measured Cl(-) activities was higher than the directly measured intraluminal potential. These data indicate that Cl(-) is actively transported out of the follicular lumen in turtle thyroid gland. On the other hand, the calculated K(+) equilibrium potential was not different from the directly measured potential, which indicates that K(+) is probably distributed passively according to the electrochemical gradients between the interstitial and the luminal compartments in turtle thyroid gland. Results obtained from the specific liquid ion-exchanger microelectrode studies correlate well with those obtained from previous radioautographic observations and chemical determinations.
D000818:Animals; D001826:Body Fluids / Q000502:physiology; D002712:Chlorides / Q000502:physiology*; D004594:Electrophysiology; D007474:Ion Exchange; D008839:Microelectrodes; D011188:Potassium / Q000502:physiology*; D013961:Thyroid Gland / Q000502:physiology*; D014426:Turtles
D002712:Chlorides; D011188:Potassium