Structurally similar double-point modified analogues of 1,25-dihydroxyvitamin D₂ (1,25D₂) were screened in vitro for their pro-differentiating activity against the promyeloid cell line HL60. Their affinities towards human full length vitamin D receptor (VDR) and metabolic stability against human vitamin D 24-hydroxylase (CYP24A1) were also tested. The analogues (PRI-1730, PRI-1731, PRI-1732, PR...

BACKGROUND Vitamin D, from diet and sunlight exposure, may be associated with reduced breast-cancer risk. This study investigated if candidate gene variants in vitamin D pathways are associated with breast cancer risk, or modify the associations between breast cancer and vitamin D exposure. METHODS Breast cancer cases aged 25 to 74 years were identified from the Ontario Cancer Registry (histo...

BACKGROUND/AIM Geographic gradients in breast cancer incidence and mortality suggest that vitamin D may reduce risk. The enzyme 25-hydroxyvitamin D 24-hydroxylase (CYP24A1), which degrades the active form of vitamin D, and the vitamin D receptor (VDR) are both found in breast tissue. We investigated six polymorphisms in CYP24A1 and two in the VDR gene in association with breast cancer risk. M...

UNLABELLED Preeclampsia, a hypertensive disorder in pregnancy develops in 2-8% of pregnancies worldwide. Winter season and vitamin D deficiency have been associated with its onset. OBJECTIVE To investigate the influence of season on maternal vitamin D status and placental vitamin D metabolism. METHODS 25-OH vitamin D and 1,25-(OH)2 vitamin D were measured in maternal serum obtained during t...

Two trials were conducted to study the effect of multi-steps phase-feeding (PF) program on growth performance of broiler chickens from 1 to 24 and 1 to 39 d of age. The control group was the nutrient recommendation of Aviagen (2019) with a three-step PF program (1-10, 11-24 and 25-39 d of age). In the first trial, the control group was compared with an eight-step PF program (PF8), and in the se...

Deregulated melanogenesis is involved in melanomagenesis and melanoma progression and resistance to therapy. Vitamin D analogs have anti-melanoma activity. While the hypercalcaemic effect of the active form of Vitamin D (1,25(OH)2D3) limits its therapeutic use, novel Vitamin D analogs with a modified side chain demonstrate low calcaemic activity. We therefore examined the effect of secosteroida...

BACKGROUND Mendelian randomization (MR) studies use genetic variants mimicking the influence of a modifiable exposure to assess and quantify a causal association with an outcome, with an aim to avoid problems with confounding and reverse causality affecting other types of observational studies. AIM We evaluated genetic markers that index differences in 25-hydroxyvitamin D (25(OH)D) as instrum...

vitamin D is 25-hydroxylated in the liver, before being activated by 1alpha-hydroxylation in the kidney. Recently, the rat cytochrome P450 2J3 (CYP2J3) has been identified as a principal vitamin D 25-hydroxylase in the rat [Yamasaki T, Izumi S, Ide H, Ohyama Y. Identification of a novel rat microsomal vitamin D3 25-hydroxylase. J Biol Chem 2004;279(22):22848-56]. In this study, we examine wheth...