Differential regulation of na+,k+-atpase in the obese zucker
rat.
Ferrer-Martinez, Andreu, Antonio Felipe, F. Javier Casado, and
Mar[cedilla]cal Pastor-Anglada.
Departament de Bioqu[acute]imica i Biologia Molecular, Universitat
de Barcelona, Barcelona 08071, Spain
APStracts 3:0150R, 1996.
Expresssion of Na+,K+-ATPase in tissues from obese and lean Zucker
rats was monitored. The phosphatase activity of the sodium pump was
increased in liver and intestinal mucosa from obese animals but was
unaltered in skeletal muscle, brown adipose tissue, kidney and heart.
Induction of Na+,K+-ATPase activity was correlated with increased
[alpha]1 subunit protein amounts in liver and intestinal mucosa,
although [alpha]1 subunit mRNA levels were increased only in liver
tissue. Neither protein nor mRNA amounts for both subunits were
significantly altered in the other tissues analyzed. The only
exception was a decrease in the amount of [beta]1 protein in kidney
from obese rats. [alpha]2 subunit protein and [alpha]2 and [beta]2
mRNA levels were not altered in brown adipose tissue, heart and
soleus. In summary, this study shows that in the obese Zucker rat the
expression of the sodium pump is enhanced in those tissues which are
directly involved in nutrient uptake and processing. This adaptation
may be related to the ongoing hyperphagia and to tissue hypertrophia,
but develops in a different manner in each tissue thus suggesting
differential regulation of [alpha]1 subunit expression.
Received 30 June 1995; accepted in final form 20 March 1996.
APS Manuscript Number R406-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 23 April 96