APStracts 2:0091F, 1995.

Role of nf-kb in the regulation of inducible nitric oxide synthase in an mtal cell line. Kone, Bruce C., J[diaeresis]org Schw[diaeresis]obel, Paula Turner, Markus G. Mohaup, and Charles B. Cangro. Departments of Medicine, Physiology, and Biochemistry and Molecular Biology, and The Hypertension Center, University of Florida College of Medicine, Gainesville, FL 32610-0224

APStracts 2:0091F, 1995.

The effects of cytokines, lipopolysaccharide (LPS), 8-bromoadenosine 3':5'- cyclic monophosphate (8Br-cAMP), and pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-kB activation, on inducible nitric oxide synthase (iNOS) expression were studied in the medullary thick ascending limb of Henle's loop cell line ST-1. LPS + interferon (IF)-g__promoted a time-dependent increase in nitrite (an NO metabolite) and iNOS mRNA, and the appearance of NF-kB p50 and p65 in nuclear protein extracts. Actinomycin D, but not cycloheximide, prevented the LPS +IF-[gamma]- induction of iNOS mRNA and NO synthesis, indicating that iNOS transcriptional activation by LPS +IF-[gamma] does not require newly synthesized proteins. PDTC inhibited the LPS +IF-[gamma]-induction of NO, iNOS mRNA, and the appearance of NF-kB in nuclear protein extracts, suggesting that NF -kB mobilization and trans-activation of the iNOS gene mediates this induction. In contrast to other cell types, cycloheximide did not alter iNOS mRNA stability, and 8Br-cAMP did not alter basal or LPS +IF-[gamma]- induced NO production in ST-1 cells.

Received 8 March 1995; accepted in final form 16 May 1995.
APS Manuscript Number F79-5.
Article publication pending Am. J. Physiol. (Renal Fluid Electrolyte
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 30 May 1995.