Interaction of nitric oxide and cyclic guanosine 3',5'-monophosphate in erythropoietin production.
The present study was designed to investigate whether in vivo and in vitro erythropoietin (EPO) production is modulated by nitric oxide (NO) and cyclic guanosine 3',5'-monophosphate (cGMP). Serum levels of EPO in ex-hypoxic polycythemic mice were significantly increased after injections of 200 micrograms/kg sodium nitroprusside for 4 d. One injection of NG-nitro-L-arginine methyl ester (L-NAME) produced a significant dose-related decrease in serum levels of EPO in ex-hypoxic polycythemic mice in response to hypoxia. When EPO producing Hep3B cells were incubated in 1% O2 for 30 min, cGMP levels in the Hep3B cells were significantly elevated, compared with cells incubated in 20% O2. The elevation of cGMP by hypoxia was inhibited by L-NAME (100 microM). Sodium nitroprusside (10 and 100 microM) and NO (2 microM) also significantly increased cGMP levels in Hep3B cells. L-NAME, LY 83583 (6-Anilino-5,8-quinolinedione, a soluble guanylate cyclase inhibitor), and Rp-8-Bromo-cGMPS (Rp-8-Bromo-guanosine 3',5'-cyclic monophosphothioate, a cGMP-dependent protein kinase inhibitor) significantly inhibited the hypoxia-induced increase in medium levels of EPO in Hep3B cells. 8-Bromo-cGMPS produced a dose-dependent decrease in EPO messenger RNA levels in Hep3B cells in response to hypoxia. 8-Bromo-cGMP (10(-3) M) produced significant increases in medium levels of EPO in Hep3B cell cultures incubated under normoxic conditions, which was enhanced by the phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine (0.2 mM). These results suggest that NO and cGMP may interact in modulating hypoxic stimulation of EPO production.
Ohigashi
T
T
Tulane University School of Medicine, Department of Pharmacology, New Orleans, Louisiana 70112.
Brookins
J
J
Fisher
J W
JW
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D006152:Cyclic GMP / Q000378:metabolism*; D004921:Erythropoietin / Q000096:biosynthesis*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D051379:Mice; D008809:Mice, Inbred C3H; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000378:metabolism*; D009599:Nitroprusside / Q000494:pharmacology; D011086:Polycythemia / Q000378:metabolism; D014407:Tumor Cells, Cultured
D004921:Erythropoietin; D009599:Nitroprusside; D009569:Nitric Oxide; D001120:Arginine; D006152:Cyclic GMP; D019331:NG-Nitroarginine Methyl Ester