Immortalized rabbit cortical collecting duct cells express at1 angiotensin ii receptors. Burns, Kevin D., Laura Regnier, Agn[grave]es Roczniak, and Richard L. H[acute]ebert. Departments of Medicine and Physiology, University of Ottawa and Ottawa General Hospital, Ottawa, Ontario, Canada
APStracts 3:0155F, 1996.
Rabbit cortical collecting duct (CCD) cells were immortalized in order to study angiotensin II (Ang II) signalling in the CCD. Transfected cells retained CCD properties: arginine vasopressin (AVP), prostaglandin E2 and isoproterenol (10-7 M) all significantly stimulated cAMP production; parathyroid hormone and calcitonin had no effect on cAMP. 27% of transfected cells bound the [beta] -intercalated cell marker peanut lectin agglutinin, while antibodies against principal cells and [alpha]-intercalated cells immunolabelled 26% of cells. All cells stained with antibodies to the epithelial cell marker, cytokeratin. In contrast, no immunofluorescence was observed with antibodies to smooth muscle myosin, Tamm Horsfall protein, or factor VIII. Transfected cells demonstrated amiloride -sensitive transepithelial short circuit current. In transfected cells, radioligand binding assays detected a single class of Ang II receptors (Kd= 0.78 nM), and AT1 receptor mRNA was demonstrated by Northern analysis. Ang II (10-7 M) significantly inhibited AVP -stimulated cAMP production: lower concentrations (10-10 M) increased phosphoinositide hydrolysis. In summary, we immortalized a rabbit CCD cell line that retains characteristic morphological and hormonal properties. These cells express AT1 receptors, coupled to inhibition of cAMP and to stimulation of phosphoinositide turnover. We postulate that these signalling pathways may mediate effects of Ang II on CCD transport and cell growth. 

Received 10 August 1995; accepted in final form 28 August 1996.
APS Manuscript Number F266-5.
Article publication pending Am. J. Physiol. (Renal Fluid Electrolyte
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 19 September 1996