Immortalized rabbit cortical collecting duct cells express AT1 angiotensin II receptors

Abstract

Rabbit cortical collecting duct (CCD) cells were immortalized to study angiotensin II (ANG II) signaling in the CCD. Transfected cells retained CCD properties; arginine vasopressin (AVP), prostaglandin E2, and isoproterenol (10(-7) M) all significantly stimulated adenosine 3',5'-cyclic monophosphate (cAMP) production; and parathyroid hormone and calcitonin had no effect on cAMP. Twenty-seven percent of transfected cells bound the beta-intercalated cell marker peanut lectin agglutinin, whereas antibodies against principal cells and alpha-intercalated cells immunolabeled 26% of cells. All cells stained with antibodies to the epithelial cell marker cytokeratin. By 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 (affinity constant = 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 signaling pathways may mediate effects of ANG II on CCD transport and cell growth.