Objective      To observe the distribution and gender differences of oncomodulin (OCM) in the brain of adult mice.       Methods       Five male and 5 female adult C57/BL6 mice (3 months old) were employed in this study. Brain sections of these adult mice were stained by Nickel-intensified immunohistochemistry.        Results      Immunopositive production of OCM were widely distributed in the brain of both female and male mice. High levels of expression were found in the most areas of the olfactory bulb

cerebral cortex

hippocampus

hypothalamus and cerebellum. Moderate levels of expression were observed in the most areas of the nuclei of the cerebrum and diencephalon

while low levels of expression were detected in the substantia nigra and lateral globus pallidus. In addition

some sex-differences of OCM immunoreactivities were noticed

with significant male-predominance in some nuclei but female-dominance in other nuclei.       Conclusion      OCM is widely distributed in the brain tissue of adult mice

suggesting that it may be involved in the regulation of brain function. Meanwhile

in some nuclei of the mice

the function of OCM differs due to gender differences.