To investigate the possible role of calcium metabolism in modulating external genitalia function of she-camels, the localization and distribution of calbindin-D9k (CaBP9k) and vitamin D3 receptors (VDR) were examined immunohistochemically in samples of vestibule, vulva, and clitoris acquired during breeding and non-breeding seasons. Animals (n=6 per season) were healthy adults (5 to 10 years) with no history of reproductive tract or systemic disease. CaBP9k was expressed in the cytoplasm of epithelia, but not the stroma or muscles of all three regions examined. Moreover, CaBP9k was expressed in the superficial squamous cell layer of the vulva, and in the basal and parabasal layers of the vestibule. VDR was expressed in the nuclei of epithelia of all three regions, vestibule, vulva, and clitoris. The chondrocytes of the clitoris also expressed VDR. The expression of CaBP9k and VDR was higher during the breeding season than the non-breeding season, suggesting that external genitalia function may be dependant in part on elevated calcium metabolism during this season. |
