RESUMO
In order to better understand vitamin D3 in cattle metabolism, we quantified 1alpha-HYD and 24-HYD gene expression. In the kidneys of 35 male Nellore cattle, these were divided into a control group and two treatment groups (2 x 10(6) international units of vitamin D3 administered for 2 or 8 consecutive days pre-slaughter). Vitamin D3 supplementation resulted in a significant increase in 1alpha-HYD gene expression; however, significantly increased 24-HYD gene expression was only detected in cattle that had 8 days of supplementation. The finding of upregulation of 24-HYD due to vitamin D supplementation is in line with the expected rise in 24,25-di-hydroxy-vitamin D3 synthesis observed when plasma vitamin D3 concentrations are high, stimulating excretion by the organism. On the other hand, upregulation of 1alpha-HYD was unexpected, since vitamin D3 supplementation has been reported to impact these two genes in opposite directions. We conclude that vitamin D3 metabolism in these animals is more complex than previously reported.
Assuntos
25-Hidroxivitamina D3 1-alfa-Hidroxilase/biossíntese , Bovinos/metabolismo , Colecalciferol/farmacologia , Rim/metabolismo , Esteroide Hidroxilases/biossíntese , 25-Hidroxivitamina D3 1-alfa-Hidroxilase/genética , Animais , Cálcio/sangue , Suplementos Nutricionais , Exposição Ambiental , Expressão Gênica , Gliceraldeído 3-Fosfato Desidrogenase (NADP+)/biossíntese , Masculino , Carne , Fator 1 de Elongação de Peptídeos/biossíntese , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Proteínas Ribossômicas/biossíntese , Esteroide Hidroxilases/genética , Luz Solar , Vitamina D3 24-HidroxilaseRESUMO
BACKGROUND/AIM: Human ether à-go-go-1 (EAG1) potassium channels are promising anticancer targets. Calcitriol has antitumoural properties. This study investigated EAG1 regulation by calcitriol in normal and cancer cells. MATERIALS AND METHODS: Cancer cell lines from cervix, prostate, mammary gland, and normal placenta trophoblasts were cultured. Calcitriol was determined by HPLC. Gene and protein expression were assessed by real-time RT-PCR and western blot analysis, respectively. Calcitriol-synthesising enzyme CYP27B1 or vitamin D receptor (VDR), were transfected in cervical cancer SiHa cells. Cell proliferation was assayed with XTT. RESULTS: Calcitriol decreased EAG1 mRNA in all cell types, and EAG1 protein and proliferation in SiHa cells. VDR antagonist ZK-159222 prevented the calcitriol effect on EAG1 mRNA. CYP27B1-transfected cells produced more calcitriol and less EAG1 mRNA. EAG1 mRNA was more potently inhibited by calcitriol in VDR-transfected cells. CONCLUSION: EAG1 is a calcitriol target in normal and cancer cells and calcitriol is a potential therapy for cervical cancer.