Is nitric oxide involved in the regulation of the rat testicular vasculature?
Using immunohistochemistry, endothelial nitric oxide synthase (NOS), and neuronal NOS were localized in the endothelium of rat testicular arteries and in Leydig cells, respectively. NADPH-diaphorase activity, indicating NOS activity, however, was present only in endothelial cells. In order to examin...
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Veröffentlicht in: | Biology of reproduction 1997-05, Vol.56 (5), p.1221-1227 |
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Zusammenfassung: | Using immunohistochemistry, endothelial nitric oxide synthase (NOS), and neuronal NOS were localized in the endothelium of
rat testicular arteries and in Leydig cells, respectively. NADPH-diaphorase activity, indicating NOS activity, however, was
present only in endothelial cells. In order to examine the role of nitric oxide (NO) in the regulation of rat testicular vasculature,
intact and hCG-pretreated (50-100 IU hCG given s.c. 6 h earlier) animals were given injections of the NOS inhibitor N(G)-nitro-L-arginine
methyl ester (L-NAME), 10 mg/kg i.v.). In all rats this resulted in a major increase in blood pressure. In intact, unstimulated
animals, testicular vascular resistance was unaffected, and testicular blood flow consequently increased. In hCG-treated animals,
in contrast, vascular resistance increased in an hCG dose-related way. L-NAME treatment also increased the hCG-induced accumulation
of polymorphonuclear leukocytes in testicular venules. Treatment with N(G)-nitro-D-arginine methyl ester (D-NAME, 10 mg/kg
i.v.), an inactive isomer of L-NAME, had no effect on the testicular vasculature. The study suggests that NO plays only a
limited role in the regulation of testicular blood flow under basal conditions. After hCG treatment, however, NOS activity
appears to be increased (increased endothelial NADPH-diaphorase staining), suggesting that NO in this situation is of importance
to increase blood flow and to inhibit leukocyte accumulation. |
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ISSN: | 0006-3363 1529-7268 |
DOI: | 10.1095/biolreprod56.5.1221 |