Mìžnarodnij Endokrinologìčnij Žurnal (Apr 2022)
Modern views on the metabolism and biological effects of vitamin D
Abstract
Vitamin D is a steroid hormone that plays a crucial role in maintaining normal bone condition and calcium homeostasis. In recent years, vitamin D has become a hot topic of endocrinological research, largely Due to the COVID-19 pandemic and the likely correlation between hypovitaminosis D and a high risk of chronic lung disease and associated mortality. Recent studies have shown that vitamin D exhibits a complex multistage metabolism and acts as a hormone on many extracellular targets. This review examines some new intriguing and as yet unclear aspects of vitamin D metabolism, such as new concepts of enzyme regulation, new pleiotropic effects of vitamin D receptor activation (VDR), and epigenetic effects. The mechanisms of vitamin D synthesis in the skin, its metabolism in the hepatic cytochrome P450 system, catabolism, metabolites and transport, gene control and epigenetic modulation are considered in Detail. In addition to the well-known role of vitamin D in calcium and bone metabolism, it has many pleiotropic extraskeletal effects, including potent effects on the immune system, cardiovascular system, adipose tissue and glucose/lipid metabolism, muscle and more. Experimental studies have shown that VDRs are expressed by cancer cell lines. Recent studies have shown a link between low levels of vitamin D and almost all aspects of the metabolic syndrome, such as type 2 diabetes, fasting blood glucose, hypertension, dyslipidemia, obesity and insulin resistance. Several studies have focused on the role of vitamin D in adipose tissue biology. In particular, a negative correlation between vitamin D and leptin or resistin is shown, as well as an inverse correlation with adiponectin. Recent studies in vitamin D-deficient mice have shown impaired secretion of glucose-stimulated insulin by pancreatic islets. Vitamin D is thought to play a role in the pathogenesis and progression of cancer, and vitamin D analogues can slow cancer progression and metastasis. It is concluded that vitamin D is a molecule with several endocrine, paracrine and autocrine effects on many tissues and organs, in addition to maintaining skeletal homeostasis. Research in this area, which aims to clarify the pleiotropy of many effects of vitamin D and its metabolites, continues.
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