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Volume 94, Issue 3
Displaying 1-17 of 17 articles from this issue
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Hiroyuki Kagechika2020 Volume 94 Issue 3 Pages 119-
Published: March 25, 2020
Released on J-STAGE: March 31, 2021
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Hiroshi Tamai2020 Volume 94 Issue 3 Pages 120-
Published: March 25, 2020
Released on J-STAGE: March 31, 2021
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Yoko Fujiwara, [in Japanese], [in Japanese], Hiroyuki Kagechika2020 Volume 94 Issue 3 Pages 121-128
Published: March 25, 2020
Released on J-STAGE: March 31, 2021
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Yoshihiro Mezaki, Takahiro Masaki, Tomokazu Matsuura2020 Volume 94 Issue 3 Pages 129-132
Published: March 25, 2020
Released on J-STAGE: March 31, 2021
JOURNAL OPEN ACCESSTrends in vitamin A research were analyzed by PubMed, based on the publication date (DP) and medical subject headings (MeSH). The number of papers concerning retinoids was declined in recent 20 years. Especially, the number of retinoid papers related to nuclear receptors and neoplasm was drastically reduced. The number of retinoid papers related to chemistry was also decreased, implying that the pharmacological research of retinoids and subsequent drug discovery are difficult. On the other hand, the number of retinoid papers related to eye, immune system and metabolic diseases was relatively constant and even slightly increased recently. Future perspective deduced from these analyses is that we should pay attention to nutritional, visual, immunological and metabolic aspects of retinoids in order to solve social problems such as “hypovitaminosis”, which is still the main problem in developing countries. Furthermore, continuous effort will be needed to achieve retinoid drug discovery in the future.View full abstractDownload PDF (954K) -
Akimori Wada2020 Volume 94 Issue 3 Pages 133-136
Published: March 25, 2020
Released on J-STAGE: March 31, 2021
JOURNAL OPEN ACCESSRetinal proteins are now identfied over a thousand spiecies and classfied two family types, animal- and microbial-rhodopsins, from their origin. These proteins consist of the chromophre retinal and a seven-transmembrane helix apoprotein (opsin), and these two components were covalently bonded through a protonated Shiff base. When light energy was absorbed, the double bond isomerization of the chromophore occurred from 11-cis to all-trans in animal rhodopsins and from all-trans to 13-cis in microbial rhodopshins with a conformational structure change of the opsin, and the important biological functions such as vision, isomerization, ion-pumping and cation channels in living cells were performed. In this paper, I would like to briefly overview our investigations of retinal proteins for vision and optogenetics.View full abstractDownload PDF (963K) -
Shinya Fujii, Hiroyuki Kagechika2020 Volume 94 Issue 3 Pages 137-142
Published: March 25, 2020
Released on J-STAGE: March 31, 2021
JOURNAL OPEN ACCESSRetinoid regulates various biological phenomena, such as cell proliferation, differentiation, morphogenesis, immunity, and metabolism, by binding and activating two types of nuclear receptors, retinoic acid receptors (RARs) and retinoid X receptors (RXRs). Since the discovery of these nuclear receptors, various specific modulators for both RARs and RXRs have been developed. Among them, some RAR and RXR specific agonists including Am80 (tamibarotene), an RARα/ β-selective agonist are in clinical use. Based on the recent progress in the research on the retinoid functions, the potential clinical utilities of retinoids towards metabolic diseases, autoimmune diseases, and neurodegenerative diseases have been elucidated. Here, the development of synthetic retinoids in the last 30 years, and the future prospect of the retinoid therapy are overviewed.View full abstractDownload PDF (956K) -
Toshio Okano2020 Volume 94 Issue 3 Pages 143-149
Published: March 25, 2020
Released on J-STAGE: March 31, 2021
JOURNAL OPEN ACCESSVitamin D can only be made by sunlight exposure, and must undergo sequential metabolic activations to form its most active metabolite 1α,25(OH) 2D3 before exerting its hormonal actions in a variety of cells and tissues. 1α,25(OH) 2D3 regulates not only calcium and bone metabolism but also cell proliferation/differentiation, immune system and hormone secretion. 1α,25(OH) 2D3 binds to vitamin D receptor (VDR) and subsequent binding of the hormone-receptor complex along with Retinoid X receptor (RXR) to selected DNA sequences in chromosome induces gene expression of vitamin D-dependent proteins (a genomic action). Additionally, 1α,25(OH) 2D3 induces increases in intracellular calcium, transmembrane signaling, alterations in phospholipid metabolism and protein C kinase activity (a non-genomic action). In recent years, vitamin D research has made a remarkable progress.
This review article describes recent advances in basic and clinical vitamin D researches.View full abstractDownload PDF (1282K) -
Naoko Tsugawa2020 Volume 94 Issue 3 Pages 150-154
Published: March 25, 2020
Released on J-STAGE: March 31, 2021
JOURNAL OPEN ACCESSThree decades have passed since the 40th anniversary edition of the Fat Soluble Vitamins Research Committee was published. In the nutritional field of vitamin D, there has been a remarkable shift in the recognition of the nutritional significance of 25-hydroxyvitamin D during these three decades. This review would be focused on the significance of 25-hydroxyvitamin D, vitamin D status of Japanese people or Dietary Reference Intakes for Japanese, with looking back on researches that the committee members have been involved in.View full abstractDownload PDF (855K) -
Atsushi Kittaka2020 Volume 94 Issue 3 Pages 155-161
Published: March 25, 2020
Released on J-STAGE: March 31, 2021
JOURNAL OPEN ACCESSTachysterol 3 is a structural isomer of vitamin D3 and is produced by exposing previtamin D3 to ultraviolet light immediately after it is generated in the skin during biosynthesis of vitamin D3 from 7-dehydrocholesterol via previtamin D3 by photochemical reaction. The instability of tachysterol3 , the conversion of tachysterol3 to its stable analogs by C14-epimerization on the CD-ring hydrindane skeleton, and the unique VDR binding mode of tachysterol3 are described in this mini-review.View full abstractDownload PDF (1139K) -
Saiko Ikeda2020 Volume 94 Issue 3 Pages 162-165
Published: March 25, 2020
Released on J-STAGE: March 31, 2021
JOURNAL OPEN ACCESSIn the last 30 years, the research on vitamin E metabolism has made great progress. Initially, dietary vitamin E was thought to be absorbed by passive diffusion in the small intestine, but it has become clear that transporter proteins, such as Niemann-Pick C1-like 1 and ATP- binding cassette transporter A1, are involved in at least a part of the intestinal absorption of vitamin E. The α-tocopherol transfer protein (α-TTP) has also been shown to play an important role in maintaining levels of vitamin E in the body. Among vitamin E isoforms, α- tocopherol, which has the highest affinity for α-TTP, is preferentially transported from the liver to extrahepatic tissues. The importance of α -TTP in vitamin E metabolism has influenced the Dietary Reference Intake for Japanese. In addition, carboxyethyl-hydroxychroman was identified as the major metabolite of vitamin E. This finding revealed that vitamin E is metabolized by a kind of drug metabolism reaction.View full abstractDownload PDF (1017K) -
Koichi Abe2020 Volume 94 Issue 3 Pages 166-173
Published: March 25, 2020
Released on J-STAGE: March 31, 2021
JOURNAL OPEN ACCESSVitamin E is a physiologically essential nutrient and its deficiencies in animals are known as rat fecal resorption, rat hemolysis, chicken muscle dystrophy, chicken dystrophy, and chicken encephalomalacia. Each vitamin E deficiency in animals may connect with vitamin E insufficiencies and disorders in humans as follows: fecal resorption vs. infertility, hemolysis vs. vasodilation, muscle dystrophy vs. sarcopenia, and encephalomalacia vs. dementia.
This review pursues the history of vitamin E clinical studies based on the following parts; (1) infertility, (2) vasodilation, (3) brain function, (4) physical activity, (5) liver function, (6) periodontal function, (7) immune response, and (8) non-α-tocopherol function.View full abstractDownload PDF (883K) -
Michio Komai2020 Volume 94 Issue 3 Pages 174-177
Published: March 25, 2020
Released on J-STAGE: March 31, 2021
JOURNAL OPEN ACCESSVitamin K (VK) is a fat-soluble vitamin, and an essential factor for blood coagulation and bone structure formation. All VK analogues have an activity as a cofactor for post-translational formation of Gla-proteins (ex., clotting factors, osteocalcin (bone Gla-protein), matrix Gla-protein (MGP), and so on). Recent studies revealed that menaquinone-4 (MK-4=VK2), out of VK analogues, has specific activities for various important physiological functions. Most of the menaquinone analogues (MK-n) are synthesized by microorganisms including intestinal microbiota, but many researchers have reported that MK-4 is unique in being synthesized by the conversion of orally ingested phylloquinone (VK1) or MK-n (VK2) by endogenous enzyme action in the major tissues of higher animals. Actually, MK-4 has specific activities as follows; 1) bone resorption decreasing activity by inducing apoptosis of osteoclast cells through the suppression of RANKL, 2) apoptosis inducing activity in cultured leukemia cells (= anti-cancer activity), 3) anti-atherosclerotic activity, 4) binding activity to nuclear steroid X receptor (SXR or PXR), 5) anti-diabetic activity, 6) anti-inflammatory effect through down regulation of IL-6 expression, and 7) direct effect on inducing steroid hormone (testosterone) biosynthesis in testis, though VK1 or MK-n could be also effective when applied in vivo because ingested VK1 or MK-n can be converted into MK-4 in various tissues.View full abstractDownload PDF (940K) -
Kimie Nakagawa2020 Volume 94 Issue 3 Pages 178-183
Published: March 25, 2020
Released on J-STAGE: March 31, 2021
JOURNAL OPEN ACCESSVitamin K is a fat-soluble vitamin that plays an important role in blood coagulation and bone formation. Vitamin K has homologues due to differences in the side chain structure, phylloquinone (vitamin K1) (PK) having a phytyl side chain and menaquinones (MK - n, n = 1 to 14) having an isoprenoid side chain structure. The main vitamin K that we take from our daily diet is PK, and a fermented food, natto, contains MK-7 produced by Bacillus subtilis natto. However, the majority of vitamin K present in the tissues of mammals including humans is menaquinone-4 (vitamin K2) (MK-4) having a geranylgeranyl side chain. This reason is that PK or MK-n obtained in the diet is converted into MK-4 in the body. This phenomenon was revealed by stable isotope-labeled vitamin K study, and it was proved that the enzyme responsible for it was UbiA prenyltransferase domain containing protein 1 (UBIAD1). Recently, new vitamin K functions have been elucidated by studies using UBIAD1 gene-deficient mice. It is expected that the application of vitamin K will be expanded by clarifying the action of new vitamin K through vitamin K metabolism and conversion functions.View full abstractDownload PDF (1340K) -
Yoshitomo Suhara2020 Volume 94 Issue 3 Pages 184-189
Published: March 25, 2020
Released on J-STAGE: March 31, 2021
JOURNAL OPEN ACCESSVitamin K is generally known as a coenzyme for γ-glutamylcarboxylase (GGCX) and involved in blood coagulation and bone formation. In recent years, various new effects of vitamin K such as an agonist of nuclear receptors, an inhibitor of proliferation of liver cancer cells, and protection of neurons against oxidative stress have discovered. From these findings, derivatives of vitamin K have been synthesized and examined to obtain higher biological activities than natural vitamin K. This article introduces the recent findings of these derivatives.View full abstractDownload PDF (926K) -
Natsuo Ueda2020 Volume 94 Issue 3 Pages 190-196
Published: March 25, 2020
Released on J-STAGE: March 31, 2021
JOURNAL OPEN ACCESSLinoleic and α-linolenic acids are nutritionally essential and therefore called as essential fatty acids. In mammalian tissues, linoleic acid (18:2, ω6) can be converted to other ω6 polyunsaturated fatty acids (PUFAs) such as arachidonic acid (AA) (20:4), while α-linolenic acid (18:3, ω3) to other ω3 PUFAs such as eicosapentaenoic acid (20:5) and docosahexaenoic acid (22:6). One of the most important roles of these PUFAs is to serve as precursors of lipid mediators, which exert physiological actions through specific G protein-coupled receptors or nuclear receptors. Eicosanoids and endocannabinoids are two representative classes of lipid mediators metabolically related to AA. Eicosanoids include prostaglandins, thromboxanes, and leukotrienes, all of which are formed from AA by oxygenases like cyclooxygenase and 5-lipoxygenase, while endocannabinoids, which function as endogenous ligands of cannabinoid receptors, are the glyceryl ester or ethanolamide of AA (2-arachidonoylglycerol and anandamide, respectively). In this article, I will outline the progress in the studies on the metabolism and biological effects of eicosanoids and endocannabinoids during the past thirty years.View full abstractDownload PDF (1079K) -
Ikuyo Ichi, Yoko Fujiwara2020 Volume 94 Issue 3 Pages 197-202
Published: March 25, 2020
Released on J-STAGE: March 31, 2021
JOURNAL OPEN ACCESSIn mammals, polyunsaturated fatty acids (PUFAs) such as linoleic acid (18:2n-6) and α-linolenic acid (18:3n-3) cannot be synthesized de novo, and therefore are essential fatty acids (EFAs). EFAs and their downstream long-chain PUFAs (LC-PUFAs) such as arachidonic acid (20:4n-6), EPA (20:5n-3), and DHA (22:6n-3) are localized to cell membranes as phospholipid esters and play critical roles in regulating membrane structures, fluidity and permeability. In addition, the certain classes of PUFAs are precursors of eicosanoid such as prostaglandins and leukotrienes, and thus mediate numerous physiological processes. Essential fatty acid deficiency (EFAD) occurs when less than 1% of total calories are provided from EFA such as linoleic acid. EFAD has been related to various clinical features such as skin lesions, impaired growth, infertility and steatosis. In the EFA-deficient state, Mead acid (20:3n-9) is endogenously synthesized from oleic acid (18:1n-9). Although the significance of mead acid in an EFAD state is not well understood, Mead acid is thought to be used as a substitute for essential PUFAs in biological membranes. This article introduces the metabolism and function of dietary and endogenous PUFA including recent studies.View full abstractDownload PDF (917K) -
Ikuo yoshimura2020 Volume 94 Issue 3 Pages 203-205
Published: March 25, 2020
Released on J-STAGE: March 31, 2021
JOURNAL OPEN ACCESSDownload PDF (907K)
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