Expression of prolactin receptor (PRL-R) mRNA in the caudal gland of Hokkaido sika deer (Cervus nippon yesoensis Heude, 1884)
We applied the in situ hybridization technique to the Hokkaido sika deer (Cervus nippon yesoensis) caudal glands using probes designed from the red deer (Cervus elaphus) prolactin receptor cDNA. Prolactin receptor mRNA expression was consistently detected in the secretory epithelial cells collected from fawns and lactating hinds. This suggests that the presence of developed caudal glands during late pregnancy and lactation may be caused by increased blood levels of prolactin. During late pregnancy and lacation, visual range is limited for deer in forests and grasslands because of the flourishing leaves and sprigs. Therefore, we suggest that the scent emitted from the caudal gland in a particular season coordinates with and reinforces the visual alarm effect of the rump patch and tail.