Histologically, glandular cells, interstitial cells and excretory tubules were identified in the breeding season scented glands, whereas epithelial cells were sparse in the non-breeding season. Immunohistochemical results showed that OTR was present in epithelial cells and interstitial cells while OT, pERK1/2, ERK1/2 and c-fos were expressed in epithelial cells and glandular cells. The protein and mRNA expressions of OTR, OT and c-fos were significantly higher in the scented gland in the breeding season than in the non-breeding season. Importantly, the levels of OT in scented glands and serum were measured by hormone assays, and their concentrations were both significantly higher in the breeding season than in the non-breeding season. Moreover, bioinformatics analysis showed that the predicted targets of the differentially expressed microRNAs might include the genes encoding OTR, ERK1/2 and c-fos.
These findings suggest that OT may regulate the function of muskrat scented glands by the locally expressed receptors.
Seasonal mRNA expression of Oxt (a), Oxtr (b), Mapk3 (c), Mapk1 (d) and Fos (e) in the scented glands. The error bars represent means ± s.e.m. for five independent experiments. B, breeding season; NB, non-breeding season. * P < 0.05; *** P < 0.001.