Eur J Anat, 2 (3): 159-165 (1998)

Testosterone enhances the NADPH-diaphorase staining in the paraventricular nucleus of the hypothalamus

F. Sánchez^1,2, M.L. Herrera¹, M.T. Pérez¹,M.A. Pérez¹,G. Vázquez¹, J.L. Gutiérrez¹, M.N. Moreno³ and R.Vázquez^1,2

1.-Department of Human Anatomy and Histology. Faculty ot Medicine. Campus Unamuno. E-37007 Salamanca, Spain. 2.-Neuroscience Institute. Faculty of Medicine. Campus Unamuno. E-37007 Salamanca, Spain 3.-Department of Computing. Faculty of Sciences. Plaza de la Merced s/n. University of Salamanca. E-37007 Salamanca, Spain

ABSTRACT SUMMARYNitric 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.

Keywords: Testosterone - Nitric oxide synthase - Hypothalamus - Neuroendocrine - Rat.