Oestrogen receptor occurrence in the male mouse brain: modulation by paternal experience.

Paternal behaviour (pup-searching and retrieving of pups) was studied in male house mice with different experience in pup care and oestrogen receptor immunoreactive (ER-IR) cells were localized and quantified in their brains. Experience with pups induced paternal behaviour and correlated with (a) the occurrence of ER-IR cells in the bed nucleus of the stria terminalis, hippocampus, subiculum, lateral septal nuclei, entorhinal and piriform cortex, (b) increased numbers of ER-IR cells in the medial preoptic area and arcuate nucleus of the hypothalamus, and (c) decreased presence of ER-IR cells in the periventricular grey of the midbrain. The data indicate oestrogen receptor modulation in the male brain and suggest that oestrogen binding in distinct brain areas is involved in the regulation of paternal behaviour.