Effects of aminoguanidine on nitric oxide production induced by inflammatory cytokines and endotoxin in cultured rat hepatocytes

Table 1 Inhibitory effect of aminoguanidine and L-NAME on CM stimulated in vitro nitrite production in primary cultured rat hepatocytes

Dose (μmol·L-1)	n	c (NO2-) (μmol·L-1)	Inhibition rate (%)	Dose (μmol·L-1)	n	c (NO2-) (μmol·L-1)	Inhibition rate (%)
Control	6	6.2 ± 1.0		Control	6	6.5 ± 1.3
CM	16	12.3 ± 4.1b		CM	8	12.6 ± 3.7b
CM + Aminoguanidine				CM + Aminoguanidine
0.1	16	9.6 ± 3.9	22.0	0.1	9	10.1 ± 1.9	19.8
1	16	8.4 ± 2.6a	31.7	1	9	9.4 ± 2.5	25.4
10	16	6.9 ± 2.8d	44.0	10	9	8.5 ± 3.0a	32.5
100	16	5.7 ± 1.9d	53.7	100	9	7.7 ± 2.4a	38.9
1000	16	5.5 ± 2.1d	55.3	1000	9	7.8 ± 2.8a	38.1

CM (Cytokines mixture): IL-1β 10 KU·L^-1, TNF-α 500 KU·L^-1, and IFN-γ 100 KU·L^-1 plus LPS 10 mg·L^-1; Cultured hepatocytes were stimulated in vitro with CM in the absence or presence of inhibitors (aminoguanidine or L-NAME) at various concentrations for 24 h. Amounts of nitrite in the supernatant were assayed 24 h after start of stimulation in vitro. ^-x±s, n = 6-16 rats (3 well for each treatment in each experiment); ^bP < 0.01, compared with control, ^aP < 0.05, ^dP < 0.01 compared with corresponding CM.

Table 2 Effect of aminoguanidine, L-NAME and L-NNA on intracellular cGMP accumulation induced by CM in vitro

Groups	n	c (cGMP) (pmol·L-1)	Inhibition rate (%)
Control	7	1.29 ± 0.6
Cytokines mixture (CM)	12	3.01 ± 1.5a
CM + Aminoguanidine (0.1 mmol·L-1)	7	1.48 ± 0.8c	50.9
CM + L-NNA (0.1 mmol·L-1)	7	1.33 ± 1.1c	55.8
CM + L-NAME (0.1 mmol·L-1)	7	1.36 ± 0.4c	54.8

CM (Cytokines mixture): IL-1β 10 KU·L^-1, TNF-α 500 KU·L^-1, and IFN-γ 100 KU·L^-1 plus LPS 10 mg·L^-1; Cultured hepatocytes were stimulated in vitro with CM in the absence or presence of inhibitors (aminoguanidine, L-NAME, or L-NNA, respectively) for 24 h; Levels of intracellular cGMP were assayed 24 h after start of stimulation in vitro (CM or CM were co-incubated with inhibitors, respectively); ^-x±s, n = 7 rat or 12 rat (4 replicates for each treatment in each experiment); ^aP < 0.05 compared with control, ^cP < 0.05 compared with CM.

Table 3 Effect of AG, L-NAME, DEX or ActD on rat hepatocytes NO production stimulated by CM only in vitro

Groups	n	c (NO2-) (μmol·L-1)	Inhibition rate (%)
Control	12	6.0 ± 2.4
Cytokines mixture (CM)	12	12.1 ± 4.5b
CM + Dexamethasone (10 μmol·L-1)	12	8.1 ± 2.3c	33.9
CM + L-NAME (0.1 mmol·L-1)	12	7.8 ± 1.6c	35.5
CM + Aminoguanidine (0.1 mmol·L-1)	12	5.8 ± 1.1d	52.2
CM + Actinomycin D (0.2 ng·L-1)	15	5.7 ± 2.3d	53.8

CM (Cytokines mixture): IL-1β 10 KU·L^-1, TNF-α 500 KU·L^-1, and IFN-γ 100 KU·L^-1 plus LPS 10 mg·L^-1; cultured hepatocytes were harvested from rats that control group stimulated in vitro with CM in the absence or presence of inhibitors (AG, L-NAME, ActD or DEX, respectively) for 24 h; the amount of nitrite in the supernatant was assayed 24 h after start of stimulation in vitro. ^-x±s, n = 12 or 15 rats (3 wells for each treatment in each expriment); ^bP < 0.01, compared with control. ^cP < 0.05, ^dP < 0.01, compared with CM.