Evolution and Function of Vitamin D

Abstract

It is remarkable that phytoplankton and zooplankton have been producing vitamin D for more than 500 million years. The role of vitamin D in lower nonvertebrate life forms is not well understood. However, it is critically important that most vertebrates obtain an adequate source of vitamin D, either from exposure to sunlight or from their diet, in order to develop and maintain a healthy mineralized skeleton. Vitamin D deficiency is an unrecognized epidemic in most adults who are not exposed to adequate sunlight. This can precipitate and exacerbate osteoporosis and cause the painful bone disease osteomalacia. Once vitamin D is absorbed from the diet or made in the skin by the action of sunlight, it is metabolized in the liver to 25-hydroxyvitamin D [25(OH)D] and then in the kidney to 1,25-dihydroxyvitamin D [1,25(OH) 2 D]. 1,25(OH) 2 D interacts with its nuclear receptor (VDR) in the intestine and bone in order to maintain calcium homeostasis. The VDR is also present in a wide variety of other tissues. 1,25(OH) 2 D interacts with these receptors to have a multitude of important physiological effects. In addition, it is now recognized that many tissues, including colon, breast and prostate, have the enzymatic machinery to produce 1,25(OH) 2 D. The insights into the new biological functions of 1,25(OH) 2 D in regulating cell growth, modulating the immune system and modulating the renin-angiotensin system provides an explanation for why diminished sun exposure at higher latitudes is associated with increased risk of dying of many common cancers, developing type 1 diabetes and multiple sclerosis, and having a higher incidence of hypertension. Another calciotropic hormone that is also produced in the skin, parathyroid hormone-related peptide, is also a potent inhibitor of squamous cell proliferation. The use of agonists and antagonists for PTHrP has important clinical applications for the prevention and treatment of skin diseases and disorders of hair growth.

Association between dietary calcium and vitamin D intake and cervical carcinogenesis among Japanese women

“…The absorption of vitamin D and calcium are influenced by smoking (Brot et al, 1999;Ilich et al, 2002), heavy alcohol intake (Rapuri et al, 2000) and phytoestrogen (Arjmandi et al, 2002;Cross et al, 2006). Therefore, the inverse associations in our study might be attenuated among (Holick, 2003;Reichrath, 2007). In addition, Friedrich et al (2002Friedrich et al ( , 2003 indicated that messenger RNA and protein Calcium, vitamin D and cervical neoplasia risk S Hosono et al Calcium, vitamin D and cervical neoplasia risk S Hosono et al (Heaney, 2008).…”

Vitamin D supplementation guidelines

“…In evolutionary terms, vitamin D is one of the oldest hormones, that is also produced by some of the earliest phytoplankton life forms (33,34 It is known that the local production of 1,25(OH)2D followed by its binding to VDR is responsible for upregulation of approximately 2,000 genes that are involved in many metabolic pathways (29,33).…”

Melanocyte Receptors: Clinical Implications and Therapeutic Relevance

“…. 1,25(OH)2D3 has pleiotropic activities that, in addition to regulation of calcium metabolism, also acts as a potent regulator of cell growth, differentiation, apoptosis, and immune and endocrine functions [126][127][128][129]. The signaling pathway of 1,25(OH)2D3 uses the vitamin D nuclear receptor (VDR), which is a transcription factor for 1,25(OH)2D3 target genes that have a major inhibitory effect on the G1/S checkpoint of the cell cycle by up-regulating the cyclin-dependent kinase inhibitors p27 and p21, and by inhibiting cyclin D1.…”