Toxic effects of methoxychlor on the episodic prolactin secretory pattern: Possible mediated effects of nitric oxide production

Table 1 Mean serum prolactin levels, absolute and relative pulse amplitude, frequency and duration of the pulses, and mean half-life of prolactin, in adult male rats.

Group	rPRL-RP3 (ng/mL)	Absolute Amplitude (ng/mL)	Relative amplitude (%)	Frequency (Pulses/3 h)	Duration (min)	Half-life (min)
Control	0.56 ± 0.11	0.43 ± 0.05	1.92 ± 0.23	5.17 ± 0.4	29.87 ± 3.92	20.19 ± 2.37
L-NAME	0.97 ± 0.10**	0.59 ± 0.03*	1.29 ± 0.39	4.90 ± 0.2	30.03 ± 2.39	19.06 ± 1.44
MTX	1.26 ± 0.26*	0.73 ± 0.08**	0.85 ± 0.17**	5.50 ± 0.5	27.01 ± 1.56	16.18 ± 0.81
MTX + L-NAME	1.02 ± 0.27	0.32 ± 0.11^#,&	0.77 ± 0.21**	5.25 ± 0.4	29.50 ± 2.10	25.30 ± 3.74^#

The relative pulse amplitude was calculated as the quotient between absolute pulse amplitude and preceding nadir value. Values are expressed as mean ± S.E.M. The number of animals per group is 8. *P ≤ 0.05 ≤; **P ≤ 0.01 vs. Control; ^#P ≤ 0.05 vs. MTX group; ^&P ≤ 0.05 vs. NAME group.
Control group: the animals were ip injected with saline 60 minutes before beginning of the bleeding period, and vehicle 0.5 mL of sesame oil (vehicle in which MTX was administered in MTX group) for 1 month.
L-NAME group: the animals were i.p. administered N^w-nitro-L-arginine methyl ester (L-NAME) at a dose of 10 mg/kg in saline, 60 minutes before beginning of the bleeding period.
MTX group: the animals were sc treated with methoxychlor (25 mg/kg/day) for 1 month.
MTX + L-NAME group: the animals were s.c. treated with methoxychlor (25 mg/kg/day) for 1 month and L-NAME at a dose of 10 mg/kg in saline, 60 minutes before beginning of the bleeding period.