The presence of vitamin D3 metabolic system in the ovary of Prussian carp (Carassius gibelio Bloch) – preliminary study on the potential role in the final oocyte maturation process

Abstract

This study aimed to immunolocalize vitamin D₃ (VD) metabolic enzymes (CYP27B1 and CYP24A1) and receptors (VDR and PDIA3) in the ovary of Prussian carp during the spawning season. Furthermore, the effect of VD on the final oocyte maturation measured as the percentage of germinal vesicle breakdown (GVBD) after 24 h of incubation, was investigated. We have shown, for the first time, the cytoplasmic CYP27B1, CYP24A1, and PDIA3 protein immunolocalization in the ovarian follicular cells. We have also confirmed the presence of VDR in the nuclei of follicular cells. Furthermore, we have shown the stimulating effect of VD on the final oocyte maturation in fish. Therefore, VD may contribute to the regulation of ovarian functions by activation of its receptors (VDR and/or PDIA3) and/or via the paracrine/autocrine action ensured by important metabolic enzymes, namely CYP27B1 and CYP24A1.