The present series of experiments examined selected brain regions to determine the effects of the gonadal steroids, estrogen and testosterone, on the reactivity of the nitric oxide synthase, NADPH-diaphorase. The results of the first experiment indicated that estrogen administration significantly increased NADPH-diaphorase reactivity 29% in the horizontal limb of the diagonal band of Broca, while testosterone administration significantly reduced NADPH-diaphorase reactivity 27% in the vertical limb of the diagonal band of Broca. The results of the second experiment indicated that 11.8% of NADPH-diaphorase neurons in the vertical limb of the diagonal band of Broca also were immunoreactive for the androgen receptor, while 7.8% of NADPH-diaphorase neurons in the horizontal limb of the diagonal band of Broca additionally were immunoreactive for the androgen receptor. In the ventromedial nucleus of the hypothalamus, however, 90.7% of NADPH-diaphorase also were immunoreactive for the androgen receptor. The results of a third experiment indicated that NADPH-diaphorase reactivity in the ventromedial nucleus of the hypothalamus was significantly increased by 40% in intact female rats sacrificed during proestrus when compared to gonadectomized female rats. NADPH-diaphorase reactivity in either the vertical limb or horizontal limb of the diagonal band of Broca did not significantly fluctuate over the estrous cycle in intact female rats sacrificed during diestrus, proestrus, or estrus. The results of a fourth experiment indicated that NADPH-diaphorase reactivity was not significantly decreased in the diagonal band of Broca of intact male rats when compared to castrated male rats. Collectively, these results indicate that experimental titers of the steroid hormone, testosterone, reduce the reactivity of the nitric oxide synthase, NADPH-diaphorase, in the diagonal band of Broca of male rats. Physiological titers of testosterone, however, do not significantly reduce the reactivity of NADPH-diaphorase in the diagonal band of Broca of male rats. Testosterone may affect NADPH-diaphorase reactivity by a genomic mechanism, as a population of NADPH-diaphorase neurons also were immunoreactive for the androgen receptor. In addition, the present results indicate that experimental titers of the steroid hormone, estrogen, increase the reactivity of NADPH-diaphorase in the diagonal band of Broca of female rats. Alternatively, physiological titers of estrogen do not significantly increase the reactivity of NADPH-diaphorase in the diagonal band of Broca of female rats. However, physiological titers of estrogen do significantly increase the reactivity of NADPH-diaphorase in the ventromedial nucleus of the hypothalamus. These results are in general agreement with previous reports that indicate experimental titers of estrogen increase the reactivity of NADPH-diaphorase, and additionally indicate that NADPH-diaphorase reactivity in the ventromedial nucleus of the hypothalamus is significantly increased during the estrous cycle of intact cycling female rats / acase@tulane.edu
| Identifer | oai:union.ndltd.org:TULANE/oai:http://digitallibrary.tulane.edu/:tulane_27149 |
| Date | January 1996 |
| Contributors | Hebert, Thomas Joseph (Author), Dohanich, Gary P (Thesis advisor) |
| Publisher | Tulane University |
| Source Sets | Tulane University |
| Language | English |
| Detected Language | English |
| Rights | Access requires a license to the Dissertations and Theses (ProQuest) database., Copyright is in accordance with U.S. Copyright law |
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