Interleukin-1 beta induces nitric oxide production by a mouse pituitary tumour cell line (AtT20/D16).
To elucidate whether anterior pituitary cells express the nitric oxide (NO) synthase gene, we studied the synthesis of NO and the expression of NO synthase (NOS) mRNA by a mouse pituitary tumour cell line (AtT20/D16). Interleukin-1 beta (IL-1 beta) stimulated production of NO2-/NO3-(NOx) in a time-dependent manner and both NOx and cyclic GMP formation were stimulated in a dose-dependent manner by IL-1 beta. IL-1 beta-induced NOx production and intracellular cyclic GMP formation were similarly blocked by an NO synthase inhibitor, NG-monomethyl-L-arginine (LNMMA), whose effect was reversed by L-arginine, but not by D-arginine. Dexamethasone inhibited IL-1 beta-induced NOx production in a dose-dependent manner. A calmodulin inhibitor (W-7) showed no effect on IL-1 beta-induced NOx production, whereas cycloheximide and the actinomycin D completely inhibited NOx production. Northern blot analysis using cDNA for mouse macrophage-inducible NOS as a probe revealed the expression of inducible NOS mRNA in the cells only after exposure to IL-1 beta. Although IL-1 beta stimulated ACTH release from tumour cells, LNMMA failed to affect ACTH release stimulated by IL-1 beta. These results demonstrate for the first time that a pituitary tumour cell line (AtT20/D16) possesses cytokine-inducible and Ca2+/calmodulin-independent NOS, although NO may not be involved in ACTH release.
Ohta
K
K
Second Department of Internal Medicine, Tokyo Medical and Dental University, Japan.
Hirata
Y
Y
Imai
T
T
Marumo
F
F
D000594:Amino Acid Oxidoreductases / Q000235:genetics*; D000818:Animals; D015152:Blotting, Northern; D006152:Cyclic GMP / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D007700:Kinetics; D051379:Mice; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D011994:Recombinant Proteins / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D007375:Interleukin-1; D012333:RNA, Messenger; D011994:Recombinant Proteins; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D006152:Cyclic GMP