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Effects of nitric oxide on proliferation and differentiation of rat brown adipocytes in primary cultures
Author(s) -
Nisoli Enzo,
Clementi Emilio,
Tonello Cristina,
Sciorati Clara,
Briscini Luca,
Carruba Michele O
Publication year - 1998
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1038/sj.bjp.0702131
Subject(s) - nitric oxide , primary (astronomy) , endocrinology , microbiology and biotechnology , chemistry , medicine , nitric oxide synthase , biology , physics , astronomy
1 In the present work, we study the effect of NO on the proliferation and differentiation of brown fat cells in primary cultures. 2 Brown fat precursor cells isolated from rat brown adipose tissue were cultured for 8 days until confluence and treated daily with the NO donating agents, S‐nitroso‐acetyl penicillamine (SNAP) or S‐nitroso‐ L ‐glutathione (GSNO). Both agents (300 μ M ) decreased cell proliferation approximately 8 fold on day 8. The inhibitory effect of NO was unlikely to be due to cytotoxicity since (i) cells never completely lost their proliferation capacity even after 8 days of exposure to repeated additions of SNAP or GSNO, and (ii) the inhibitory effect was reversible after removal of the media containing NO donors. 3 Daily treatment with nitric oxide synthase inhibitors, such as N G ‐nitro‐ L ‐arginine methyl ester ( L ‐NAME, 300 μ M ), led to the stimulation of cell proliferation by 44±5%, n =3, suggesting that NO, endogenously produced in brown adipocytes, may be involved in modulating cell growth. 4 Daily treatment with both SNAP or GSNO induced significant mitochondriogenesis, measured as the mitochondrial conversion of 3‐[4,5‐dimethylthiazol‐2‐yl‐]‐2,5‐diphenyl tetrazolium bromide (MTT) to formazan, whilst daily treatment with L ‐NAME was without effect. 5 The inhibition of cell proliferation by NO donors was accompanied by the expression of two genes coding for peroxisome proliferator activated receptor‐γ and uncoupling protein‐1, which are upregulated during differentiation. 6 Increasing cyclic GMP in cells by 8‐bromo‐cyclic GMP (100–1000 μ M ) did not reproduce the observed NO effects on either cell number or gene expression. On the other hand, chronic treatment with the inhibitor of the NO‐stimulated guanylyl cyclase, 1H‐[1,2,4]oxadiazole[4,3‐a]quinoxalin‐1‐one (ODQ), reduced the expression of peroxisome proliferator activated receptor‐γ and uncoupling protein‐1.British Journal of Pharmacology (1998) 125 , 888–894; doi: 10.1038/sj.bjp.0702131