Abstract
The effect of varying the concentration of medium K+ and Na+ on in vitro thyroidal 131I release was studied. Elevation of medium K+ to levels previously shown to depolarize thyroid membranes had no effect on thyroidal 131I release. A dependence of secretion on Na+ both in terms of 131I release and colloid phagocytosis was demonstrated by replacing Na+ with K+, choline, sucrose, or Tris. Oubain and K+-free medium, under conditions which inhibited membrane transport functions, inhibited 131I release and colloid droplet formation stimulated by both TSH and cyclic AMP. Thus activation of colloid phagocytosis by cyclic AMP appears to depend on medium Na+ and a functioning Na+- K+ transport system. (Endocrinology 90: 1452, 1972)
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call