Immunocytochemical evidence for a progesterone receptor in neurons and glial cells of the rat spinal cord

Using the KC 146 monoclonal antibody recognizing the B-form of the progeste rone receptor (PR) and immunocytochemical techniques, we investigated if PR -immunoreactive cells are present in the rat spinal cord. Neurons from vent ral horn Lamina IX, glial cells in gray and white matter and ependymal cell s were PR-positive. Evidence for estrogen-inducibility of PR in ovariectomi zed rats was not observed. There were no significant gender differences in neuronal PR immunostaining intensity in the spinal cord, measured by comput erized image ana lysis. In pituitary and uterus from estrogenized female ra ts, PR showed a strict nuclear localization, whereas in neurons and glial c ells of the spinal cord, PR localized in cytoplasm and/or nucleus and in so me cell processes. This receptor may be implicated in some of the biologica l effects of progesterone described in the spinal cord. (C) 2000 Elsevier S cience Ireland Ltd. All rights reserved.