Abstract
Li
+/Na
+ countertransport, choline transport, and intracellular Li
+ and choline were measured in the RBC of a manic-depressive subject as a function of time after termination of Li
+ therapy. Countertransport recovered from its inhibition by Li
+ in 10 days. This recovery involved a decrease in the Michaelis-Menten parameter
K
m, without change in
V
max. RBC choline decreased, and choline influx rose, much more slowly back towards pre-Li
+ values over the course of two months. Thus, choline transport was still inhibited long after Li
+ levels in RBC and plasma had become undetectable. Measurements on age-separated RBC fractions showed that recovery of choline transport was mainly in the young-cell fraction. Hence inhibition of choline transport by Li
+ may be irreversible at the level of the individual RBC.
