Nova Publishers
My Account Nova Publishers Shopping Cart
HomeBooksSeriesJournalsReference CollectionseBooksInformationSalesImprintsFor Authors
            
  Top » Catalog » Books » Biology » Nutrition » New Topics in Vitamin D Research chapters » My Account  |  Cart Contents  |  Checkout   
Quick Find
  
Use keywords to find the product you are looking for.
Advanced Search
What's New? more
Fetal Alcohol Syndrome: Recognition, Differential Diagnosis and Long-Term Effects
$73.80
Shopping Cart more
0 items
Information
Shipping & Returns
Privacy Notice
Conditions of Use
Contact Us
Bestsellers
01.Vitamin D as a Neurosteroid Hormone: From Neurobiological Effects to Behavior (pp. 29-65)
02.Is Calcidiol an Active Hormone? (pp. 1-28)
03.Vitamin D Use among Older Adults in U.S.: Results from National Surveys 1997 To 2002 (pp. 181-198)
Notifications more
NotificationsNotify me of updates to Is Calcidiol an Active Hormone? (pp. 1-28)
Tell A Friend
 
Tell someone you know about this product.
Is Calcidiol an Active Hormone? (pp. 1-28) $25.00
Authors:  Yan-Ru Lou and Pentti Tuohimaa (University of Tampere, Finland)
Abstract:
Vitamin D3 is produced in the skin during exposure to sunlight and is then 25-hydroxylated in the liver, yielding the major circulating metabolite 25-hydroxyvitamin D3 (25OHD3, calcidiol). Calcidiol is converted to 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) mainly in the kidney by 25OHD3-1-hydroxylase (1-hydroxylase). Calcidiol and 1,25-(OH)2D3 are further hydroxylated into less active metabolites by 25OHD3-24-hydroxylase (24-hydroxylase, CYP24). Vitamin D3 metabolites exert their effects by binding to the nuclear vitamin D receptor. 24-Hydroxylase is highly inducible by vitamin D3 metabolites at transcriptional level and it controls the biological action of calcidiol and 1,25-(OH)2D3. It has been proposed that the local production of vitamin D metabolites is important.
Calcidiol is generally considered a prehormone, which is activated via 1-hydroxylation. 1,25-(OH)2D3 plays a central role in calcium homeostasis but only at hypercalcemic (pharmacological) concentrations it regulates the proliferation and differentiation of various cell types in vivo and in vitro. However, we show direct evidence that calcidiol at physiological concentration possesses an inherent hormonal activity. Other hormonal factors can enhance vitamin D action by inhibiting its degradation. 5-dihydrotestosterone (DHT) and all-trans-retinoic acid (ATRA) enhance antiproliferative activities of calcidiol and 1,25-(OH)2D3 by suppressing the expression of 24-hydroxylase, which suggests that both at physiological concentrations combined with DHT or ATRA are active and can be used for therapeutic purposes. The novel vitamin D3 endocrine system of calcidiol seems to explain the discrepancies of the epidemiological and clinical data on the association between vitamin D insufficiency and many chronic diseases. We propose that calcidiol is more potent hormone regulating cell proliferation and differentiation than calcitriol in the physiological condition. Therefore, seasonal fluctuation of calcidiol might be directly involved in the development of chronic diseases. 


Available Options:
Version:
Customers who bought this product also purchased

High Levels of Active 1,25-Dihydroxyvitamin D Despite Low Levels of the 25-Hydroxyvitamin D Precursor - Implications of Dysregulated Vitamin D for Diagnosis and Treatment of Chronic Disease (pp. 1-23)
Special Focus Titles
01.Violent Communication and Bullying in Early Childhood Education
02.The New Science of Curiosity
03.Cultural Considerations in Intervention with Women and Children Exposed to Intimate Partner Violence
04.Chronic Disease and Disability: The Pediatric Lung
05.Fruit and Vegetable Consumption and Health: New Research
06.Future Perspectives on Nigella sativa: Characterization and Pharmacological Properties
07.Wine and Winemaking: The Value and Efficiency
08.Impacts and Challenges in Oil Palm Cultivation and Downstream Applications of Biomass
09.Fire and the Sword: Understanding the Impact and Challenge of Organized Islamism. Volume 2
10.The Life and Times of the World's Most Famous Mathematicians
11.Innovation Processes in the Social Space of the Organization
12.High-Strength Steels: New Trends in Production and Applications

Nova Science Publishers
© Copyright 2004 - 2018

Is Calcidiol an Active Hormone? (pp. 1-28)