Oestrogenic regulation and differential expression of WNT4 in the bonnet monkey and rodent epididymis.

A role for oestrogen in regulating fluid reabsorption in the monkey epididymis was recently demonstrated. Here, these studies are extended to identify potential oestrogen-regulated proteins in the cauda region of monkey epididymis treated with vehicle and oestrogen receptor antagonist (ICI 182780). Two-dimensional electrophoretic analysis was used to identify the proteins. The results indicated down-regulation of WNT4 in the ICI-182780-treated monkey cauda. In addition, the Wnt4 mRNA concentration was also reduced in the caput regions of ICI-182780- treated rats and oestrogen receptor knockout mice. WNT4 is a key regulator of gonadal differentiation in humans and mice and plays a pivotal role in early mouse embryogenesis. The results of the present study establish the presence of WNT4 in the monkey epididymis and its regulation by oestrogen, and suggest a role for WNT4 in maintaining epididymal homeostasis.