Artigo de Periódico
Prolactin secretion in hypothyroid endotoxemic rats: involvement of l-arginine and Nitric Oxide synthase
Fecha
2005Registro en:
1073-2322
v. 23, n. 5
Autor
Rodriguez, Tânia Tavares
Biscarde, Eduardo Ferreira da Silva
Muniz, Relva de Freitas Diniz Goncalves
Amoedo, Maurício Kauark
Ramalho, Maria José Pedreira
Rodriguez, Tânia Tavares
Biscarde, Eduardo Ferreira da Silva
Muniz, Relva de Freitas Diniz Goncalves
Amoedo, Maurício Kauark
Ramalho, Maria José Pedreira
Institución
Resumen
The identification of nitric oxide (NO) within the hypothalamus and pituitary gland has suggested its role as modulator of the activity on hypothalamic-pituitary axis. Hypothalamic NO synthase (NOS) is known to be regulated by thyroid hormones. We investigated the effects of previous injection of N[omega pi]-nitro-L-arginine methyl ester (L-NAME), a NOS inhibitor, and L-arginine (L-Arg), the substrate for NO synthesis, on prolactin (PRL) secretion, through the lipopolysaccharide (LPS)-induced inflammatory response in thyroidectomized (TX) rats. TX or sham-operated (N) rats were intraperitoneally (i.p.) injected with L-NAME (10 mg kg-1) or L-Arg (200 mg kg-1) or the same volume of vehicle (saline solution) 30 min before endotoxemia-induction with LPS at 250 µg (100 g body weight)-1, i.p.. In N rats, NO increased PRL release in response to endotoxemia, whereas in hypothyroid rats, NO appeared to have the opposite effect. Our data support the hypothesis that NO exerts a modulatory influence on PRL secretion after LPS-induced inflammatory response.