Regulation of the polymeric immunoglobulin receptor by water intake
and vasopressin in the rat kidney.
Rice, James C., Jeff S. Spence, Judit Megyesi, Robert L. Safirstein,
and Randall M. Goldblum.
Departments of Internal Medicine and Pediatrics, The University of
Texas Medical Branch at Galveston, Galveston, Texas 77555
APStracts 5:0025F, 1998.
The polymeric immunoglobulin receptor (pIgR) transports polymeric
immunoglobulins (IgA) from the basolateral to the apical surface of
epithelial cells. At the apical surface, its amino-terminal domain,
termed secretory component (SC), is proteolytically cleaved and
released either unbound (free SC) or bound to IgA. We examined the
effects of changes in water balance and vasopressin on the production
and secretion of the pIgR in the rat kidney in vivo. Water
deprivation induced a 2.7 fold increase in the pIgR mRNA and a 2.2
fold increase in intracellular pIgR protein compared to water loaded
animals. Physiologic doses of desmopressin reproduced the effects of
water deprivation on mRNA and intracellular protein levels,
suggesting that pIgR expression may be regulated by a vasopressin
-coupled mechanism. Secretion of free SC and sIgA in the urine
however, correlated directly with water intake and urine flow. These
results suggest that hydration status and vasopressin may affect the
mucosal immunity of the kidney, by regulating at different steps,
epithelial cell production and secretion of the polymeric
immunoglobulin transporter/secretory component.
Received 23 May 1997; accepted in final form 22 January 1998.
APS Manuscript Number F173-7.
Article publication pending Am. J. Physiol. (Renal Physiology).
ISSN 1080-4757 Copyright 1998 The American Physiological Society.
Published in APStracts on 28 January 1998