Abstract: | The possible localization of nitric oxide (NO) synthase (NOS) in proximity to the microvasculature was examined in the rat adenohypophysis using immunohistochemistry and nicotinamide adenine dinucleotide phosphate diaphorase histochemistry. A population of NOS-positive cells was localized in very close contact with the sinusoidal capillaries. The pattern of this perivascular localization was either unicellular, bicellular or multicellular. These observations suggest that, at least, some actions of NO in the adenohypophysis can be accounted for by a local regulation of the glandular microvasculature. |