REDUCED NICOTINAMIDE ADENINE-DINUCLEOTIDE PHOSPHATE DIAPHORASE ACTIVITY IN THE PARAVENTRICULAR NUCLEUS OF THE RAT HYPOTHALAMUS IS MODULATEDBY ESTRADIOL

Based on previous studies demonstrating that reduced nicotinamide aden ine dinucleotide phosphate (NADPH)-diaphorase (ND) activity is modulat ed by estradiol and the discovery of a new subtype of estrogen recepto r highly expressed in the paraventricular nucleus of the hypothalamus (PVN), a possible estrogen influence on this activity was investigated in the neuronal populations (magno- and parvicellular) of this nucleu s. Cryostat sections were cut and processed for the histochemical dete ction of the ND activity. Following ovariectomy (14 days), numerical d ata displayed a slight decrease in the number of ND-neurons, especiall y in the posterior magnocellular and the medial parvicellular subdivis ions, which was reversed after daily treatment with estradiol benzoate . Administration of estradiol benzoate to male rats (14 days) induced a significant increase (P < 0.05) in the number of ND-neurons, mainly at the level of the posterior magnocellular subdivision. These data in dicate that paraventricular ND-neurons are influenced by estradiol. (C ) 1998 Elsevier Science Ireland Ltd. All rights reserved.