Red Blood Cell
Triiodothyronine Uptake as Membrane Parameter of Depression
L. KALIŠOVÁ-STÁRKOVÁ, Z. FIŠAR, I. PACLT, Z.
HANUŠ, J. VEVERA
Department of Psychiatry, First Faculty of Medicine, Charles
University, Prague, Czech Republic
Received December 30, 2004
Accepted April 20, 2005
On-line May 24, 2005
Summary
We tested the hypothesis considering the role of
hypothalamic-pituitary-thyroid axis (HPT), L-triiodothyronine
(L-T3) uptake into erythrocytes, and the role of membrane lipids
in the development and treatment of affective disorders. Changes
in kinetic parameters (Vmax, maximal velocity and KM, apparent
Michaelis constant) of L-T3 uptake into red blood cells (RBCs)
and changes in membrane fluidity in a group of 24 patients with
major depression were measured before treatment and after 1
month of treatment with citalopram. Parameters Vmax and KM, as
well as membrane microviscosity, were significantly increased in
depressed patients both before and after treatment in comparison
with healthy subjects. We concluded that the function of the
membrane transporter for L-T3 in RBC is changed in depression.
This change is probably connected with alteration of membrane
fluidity and/or transporter–lipid interactions. We did not find
any normalization of the measured parameters after 1 month of
treatment. The results show the importance of composition and
physical properties of the lipid bilayer for transmembrane
transport of L-T3 and support the hypothesis that the HPT axis
is in depression.
Key words
Depression • Erythrocyte • Membrane fluidity • Triiodothyronine
• Uptake
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