Resumen de Testosterone enhances the NADPH-diaphorase staining in the paraventricular nucleus of the hypothalamus
Fernando Sánchez Hernández, M. Luz Herrera San Millan, M. Teresa Perez Menendez, María de los Ángeles Pérez de la Cruz 
, G. Vázquez, J.L. Gutiérrez, María Navelonga Moreno García , Ricardo Vázquez
Nitric oxide is involved in mechanisms which underlie neuroendocrine events in reproduc tion. Since gonadal steroids have profound effects on reproductive function, it is of interest ro examine whether nitric oxide synthase acti vity is altered by gonadal steroid hormones in specific nuclei of the hypothalamus. In the para ventricular nucleus of the hypothalarnus, chan ges of nitric oxide synthase/NAOPH-diaphorase staining have been shown to occur after an important number of experimental conditions. Basecl on previous studies demonstrating that NAOPH-diaphorase activity in the paraventricu lar nucleus of the hypothalamus is modulated by estradiol, a possible anclrogen influence on this activity was ínvestígated in the neuronal populations (magno- and parvicellular) of this nucleus. Cryostat sections were cut and proces sed for the histochemícal cletection of the NAOPH-cliaphorase activity. Following orchi-"dectomy (14 days), numerical data displayed adecrease in the number of NAOPH-neurons, especially in the posterior magnocellular and the medial parvicellular subdívisions (p < 0.05), which was reversed after daily treatrnent with testosterone. These data indica te that paraven tricular NAOPH-diaphorase neurons are influen ced by testosterone.
