Organic osmolyte distribution and levels in the mammalian urinary
bladder in diuresis and antidiuresis.
Kwon, Eugene D., John A. Dooley, Kyu Yong-Jung, Peter M. Andrews,
Arlyn Garcia-Perez, and Maurice B. Burg.
Laboratory of Kidney and Electrolyte Metabolism, National Heart,
Lung, and Blood Institute
APStracts 3:0064F, 1996.
Inositol, sorbitol, glycerophosphocholine (GPC), and betaine are
organic osmolytes that are accumulated by renal medullary cells in
response to hyperosmotic stress. Previous screening studies, using
nuclear magnetic resonance spectroscopy (NMR), have shown some of
these same compounds to be present in extracts of whole urinary
bladder from rabbits and rats. In the present study, we used high
performance liquid chromatography (HPLC) to quantify levels of these
compounds in the separated epithelium and muscle of bladders taken
from normal rabbits as well as diuretic and thirsted rats. We find
that: 1) high concentrations of organic osmolytes, namely inositol,
GPC, and sorbitol, are present in urinary bladder; 2) levels of these
osmolytes in the of the bladder epithelium are higher than in the
muscle; 3) increased urinary osmolality due to antidiuresis is
associated with a 2.4-fold increase in total osmolyte levels in rat
bladder epithelium, and a lesser (1.5-fold) increase in the muscle,
compared to corresponding levels in tissues from diuretic animals;
and 4) these increases in total osmolyte amounts in the epithelium
are due to increased levels of GPC, sorbitol, and perhaps inositol (p
= .07), whereas only GPC increases in the bladder muscle.
Received 18 December 1995; accepted in final form 21 March 1996.
APS Manuscript Number F417-5.
Article publication pending Am. J. Physiol. (Renal Fluid Electrolyte
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 1 April 96